The Israel Koschitzky Virtual Beit Midrash

Surf A Little Torah
Yeshivat Har Etzion




By Rav David Silverberg


            We read in Parashat Beshalach that after Benei Yisrael's miraculous crossing through the Sea of Reeds, they entered the wilderness of Shur, where "they went three days in the wilderness without finding water" (15:22).  The Mekhilta on this verse, and the Gemara in Masekhet Bava Kama (82a), famously comment that "water" in this verse refers to Torah, which is often likened to water.  (The source of this analogy is Yeshayahu 55:1: "O, all who thirst shall go to water," which Chazal understood as a reference to those who "thirst" for knowledge.)  Benei Yisrael went three days without studying Torah, and, as a result, they "rebelled" – as the Mekhilta describes – by angrily complaining to Moshe about the lack of water.  The Mekhilta and Gemara add that as a result of this incident Moshe enacted that the Torah should be read several times a week (on Mondays, Thursdays and Shabbat) to ensure that Benei Yisrael would not go without Torah for three complete days.


            The association between Torah and water has been explained in many different ways.  One point of comparison between Torah and water involves the quality of cleansing.  Just as water is the primary cleansing agent used to eliminate dirt, so does Torah study have the capacity to "cleanse" an individual.  Beyond simply conveying knowledge and practical instructions for religious life, Torah study has a cathartic, spiritual effect on the individual, and in this sense the Torah is indeed comparable to water.


            Rav Yehuda Leib Ginsburg, in his Yalkut Yehuda, observes that in this sense, the analogy drawn between water and Torah becomes particularly meaningful in the context of this verse.  Chazal here attribute Benei Yisrael's impatience and disrespect towards Moshe to the fact that they had had no exposure to Torah for three days.  This clearly reflects the "cleansing" quality of Torah, the internal, spiritual effect it has upon the student.  For this reason, perhaps, specifically here the Torah chooses to highlight this comparison between Torah and water, because this situation provides a perfect example of what can happen to a person's spiritual orientation when an extended period passes without his engagement in Torah learning.


            Of course, the precise nature of this "spiritual effect" of Torah study requires further elaboration, and one would likely discover different approaches to this issue among the various streams within Jewish thought.  (Most obviously, the Kabbalistic perspective would differ substantially from the rationalist approach to this concept.)  What is clear, however, is that Chazal perceived Torah study as something far more meaningful than a mere intellectual exercise, and acknowledged a spiritual dimension that is not shared by other academic disciplines.




            Parashat Beshalach records the shirat ha-yam – the song of praise sung by Benei Yisrael after the miracle of the splitting of the Yam Suf.  In the second verse of this song (15:2), we find the famous verse, "Zeh Keli ve-anvehu, Elokei avi va-aromemenu" – "This is My God, and I shall glorify Him; the God of my father, and I shall exalt Him."  In several places in the Talmud (e.g. Shabbat 133b), the Gemara extracts from this verse the well-known halakha of hiddur mitzva, beautifying mitzva performance by ensuring a high aesthetic standard with respect to the articles involved.  The Gemara speaks in this context of using a beautiful lulav and sukka on Sukkot, wearing a beautiful tallit, writing beautiful Sifrei Torah, and so on.


            Rav Shlomo Ha-kohen of Vilna, in his work of responsa Binyan Shlomo (siman 6), writes that he was once asked why the Gemara never mentions a requirement to purchase beautiful tefillin.  Seemingly, tefillin is no less a religious article than a tallit, Sefer Torah or lulav, and thus the obligation of hiddur mitzva should apply equally to tefillin.  Rav Shlomo devotes a lengthy essay to this topic, citing many interesting sources relevant to the issue.  For one thing, he notes, the Talmud Yerushalmi (Pei'a 1:1) indeed does include tefillin in its list of religious articles to which the requirement of "Zeh Keli ve-anvehu" applies.  As for the other sources, which omit tefillin from their lists, Rav Shlomo speculates that the obligation of hiddur mitzva perhaps pertains only to mitzva articles that are displayed in public, as we must demonstrate the importance and value with which we regard mitzvot.  Articles that are not exposed to public view, however, are not subject to the requirement of hiddur mitzva.  Now when it comes to tefillin (as we discussed last week), Halakha distinguishes between the tefillin shel yad and the tefillin shel rosh.  The tefillin shel yad is generally seen as the "private" component of the mitzva, as indicated in the Gemara in Menachot (37b), whereas the tefillin shel rosh is specifically intended to be worn in public view.  Perhaps, therefore, the Gemara did not mention tefillin in the context of hiddur mitzva, since it applies to only one component of the mitzva.


            Of course, this does not explain why the Gemara made no mention of the tefillin shel rosh, to which hiddur mitzva does apply.  Rav Shlomo Ha-kohen does not answer this question, but he does note that the Mekhilta, in its comments to this verse in Parashat Beshalach, indeed mentions "tefila na'a" – having a beautiful tefila, the singular of tefillin.  The author of Zeh Yenachamenu, a commentary on the Mekhilta, suggested emending the text of the Mekhilta to read "tefillin na'in," in the plural form.  Rav Shlomo Ha-kohen, however, observes that the Vilna Gaon, who carefully reviewed the prevalent texts of the Mekhilta and made emendations that he deemed necessary to correct them, does not make this correction.  Quite possibly, then, the Mekhilta distinguished between the two tefillin, and held that the obligation of hiddur mitzva applies only to the tefillin shel rosh.


            Rav Shlomo Ha-kohen points out that this discussion will yield practical ramifications beyond the general issue of whether one must endeavor to acquire a tefillin shel yad of high aesthetic quality.  The Shulchan Arukh (O.C. 32) codifies the ruling that the leather of tefillin must be colored specifically black.  This halakha is mentioned by the Rosh (in Halakhot Ketanot), who explains it by citing the verse, "Zeh Keli ve-anvehu."  Thus, if we accept the premise that hiddur mitzva does not apply to the tefillin shel yad, then we might conclude that the tefillin shel yad need not be colored black.


            Of course, common practice is to ensure that both tefillin are colored black.  This perhaps reflects our acceptance of the Yerushalmi's position, which requires hiddur mitzva for both the tefillin shel yad and the tefillin shel rosh.


            Tomorrow we will iy"H discuss this issue further.




            Yesterday, we discussed one aspect of the law of hiddur mitzva – the obligation to maintain high aesthetic standards in the performance of mitzvot – which Chazal extract from the verse in Parashat Beshalach (15:2), "Zeh Keli ve-anvehu" ("This is my God, and I shall glorify Him").  As we saw, Rav Shlomo Ha-kohen of Vilna posited a theory that this obligation applies only to mitzva articles used in public view, but not to articles that are not seen by the public.  On this basis, Rav Shlomo Ha-kohen raised the possibility that hiddur mitzva would apply to the tefillin shel rosh (the head tefillin), which is generally worn in full public view, but not to the tefillin shel yad, which is not intended for public display.


            Rav Shlomo Ha-kohen notes that this issue will impact upon a halakhic question addressed by the Rama in Orach Chayim (147:1).  The Rama cites the Mordekhai as maintaining that if the covering of a Torah scroll is made partially from linen and partially from fine silk, the side made from silk, which is more expensive and decorative, should face specifically inwards, towards the Sefer Torah.  The linen material, which is far cheaper and simpler, should face outward and be visible.  However, as the Rama proceeds to cite from the Beit Yosef, common practice does not follow this view.  Rather, communities traditionally chose to place the covering such that specifically the more decorative and ornamental side would face outward.  The Mishna Berura cites the Magen Avraham as ruling that synagogues should preferably follow the first position, and then records the Vilna Gaon as arguing that to the contrary, the first view has no basis and should therefore not be followed.


            Presumably, this debate revolves around the question as to whether or not the obligation of hiddur mitzva relates to public viewing.  The first position perhaps held that hiddur mitzva requires beautifying mitzva articles as an objective value, regardless of whether the beauty will be noticed or even visible altogether.  The second view, by contrast, likely believed that hiddur mitzva means publicly displaying the value and importance we afford mitzvot by ensuring high aesthetic standards in their performance.  Therefore, it is specifically the more decorative side of the covering that should face outward, to demonstrate to all who look upon the Sefer Torah just how valuable and precious we deem this religious article to be.




            The Torah tells in Parashat Beshalach of Benei Yisrael's experiences in Mara, where God miraculously sweetened the bitter waters.  Moshe then tells Benei Yisrael in the name of the Almighty, "If you heed the voice of the Lord your God, and you do that which is upright in His eyes, and you listen to His commandments and observe all His statutes, all the maladies that I cast upon Egypt I shall not cast upon you…" (15:26).

            According to one view in the Mekhilta, the phrase "ve-ha-yashar be-einav ta'aseh" – "and you do that which is upright in His eyes" – refers to honesty in the marketplace: "This refers to commerce, teaching that whoever deals honestly in commerce, such that he is pleasing to people, is considered as having fulfilled the entire Torah."


            We will not endeavor to explain philosophically why dealing honestly in business is deemed equivalent to observing the entire Torah.  We might, however, gain a somewhat clearer perspective on this equation in light of a section from Sefer Yirmiyahu, which, appropriately enough, is read as the haftara for the morning of Tisha B'Av.  The prophet cries, "If only I were in a desert, an inn for wayfarers, so that I may leave my nation and I may go away from them, for they are all adulterers, a band of betrayers" (Yirmiyahu 9:1).  Yirmiyahu expresses his disgust with the nation, all of whom have become "adulterers, a band of betrayers," and he longs for the opportunity to leave and live in some remote, isolated motel.  While at first glance he appears to bemoan the sexual offenses committed by the people, it becomes clear from the ensuing verses, in which Yirmiyahu cites God's description of the condition of the people, that he uses "adultery" allegorically as a generic reference to disloyalty and moral corruption:


They draw their tongues – their bows – with falsehood, and have earned fame in the land not for honesty; rather, they have gone from one evil to the next, and they have not known Me, says the Lord.  Beware each man of his fellow, and do not trust any brother, for every brother is scheming, and every friend is a talebearer.  Each one cheats the other, and they do not speak truthfully; they have trained their tongues to speak falsehood, they grow tired from iniquity.  You [Yirmiyahu] dwell among treachery; in their treachery they have refused to know Me, says the Lord.


            Yirmiyahu saw many awful kinds of behavior during his years as prophet.  Most prominently, perhaps, he himself was scorned and ridiculed – and ultimately imprisoned – by a stubborn, arrogant leadership that denied his stature and refused to heed his calls for repentance and to surrender to Babylonian rule.  But what made him feel like leaving his people was the reality of "beware each man from his fellow…for every brother is scheming, and every friend is a talebearer."  When the Jewish people reached the point where they could not trust one another, where each man had to beware of his brother and close friend, where there was nobody to trust, Yirmiyahu felt he no longer belongs among such a people.  The rampant deceit, dishonesty, and scheming left the prophet in a state of utter disorientation, where he was no longer capable of even associating with his people.  He therefore longed for the day when he could just pick up and leave; he would rather live alone in a remote, isolated campsite in the desert rather than be part of a nation whose members must suspect one another of cheating and lying.  Yirmiyahu's prophetic mission demanded that he remain and continue issuing his warnings about the impending destruction and exile; but otherwise, he was prepared to leave them.


            "Whoever deals honestly in commerce, such that he is pleasing to people, is considered as having fulfilled the entire Torah."  The Mekhilta was undoubtedly aware that there is much more to "fulfilling the entire Torah" than dealing honestly with one's employer, employee, associates, clients and authorities.  This passage could perhaps be understood in light of Yirmiyahu's prophecy.  So long as people deal honestly with one another, there is hope that through proper guidance and instruction, they will, over the course of time, cure the spiritual ills that currently plague society.  But when people cheat and lie to one another, when merchants sell faulty merchandise, when workers or employers fail to live up to their commitments, then the prophets despair, they can no longer work to improve such a society.  And under such circumstances, even the Almighty despairs, as Yirmiyahu's prophecy concludes, "Their tongue is a sharpened arrow, speaking treachery; in his mouth, one speaks peacefully to his fellow, while inside he plans his ambush.  Shall I not make an accounting for these, says the Lord?  Shall I not visit retribution upon a nation such as this?" (Yirmiyahu 9:7-8).




            Parashat Beshalach contains God's promise to Benei Yisrael that in reward for observing His commands, "all the maladies that I brought upon Egypt I will not bring upon you – for I am the Lord your healer" (15:26).


            Rav Chayim Berlin, son of the Netziv, commented that God works as a rofei – a "healer," or "physician" – on two distinct levels.  The first level is referred to by Rabbi Akiva in his response to an idolater who asked him to explain why pagans would occasionally enter their houses of worship ill and emerge cured (Masekhet Avoda Zara 55a).  Rabbi Akiva responded that when illness strikes a person, it comes with a certain time-frame, after which it would naturally leave and the patient would recover.  If this time-frame happens to end when an idolater prays in his house of worship, God nevertheless allows nature to take its course, and the patient thus recovers.  This reflects one level of divine healing: the body's natural capacity to fight illness and return to good health.  But on other occasions, the Almighty will cure a deserving patient even before the point when recovery is due to occur through his body's natural processes; this represents a second dimension of the Almighty's power of healing.


            Rav Chayim Berlin added that Chazal instituted two different blessings for these two different manifestations of God's medical powers.  The berakha of asher yatzar is recited after one performs his bodily functions, which clearly represents the body's God-given ability to cure itself and overcome illness.  The elimination of waste from the body is, on some level, a medical procedure, a means by which the human body rids itself of harmful substances and maintains its own well-being.  We therefore conclude the berakha by describing the Almighty as "Rofei khol basar" – the Healer of all flesh, thanking God for endowing the body of all human beings with this natural medical capacity.  In this berakha, then, we refer specifically to the first kind of healing described above, the natural processes that enable the human body to overcome illness.


            But there is a second berakha which we recite, to acknowledge the Almighty's other power of healing – the berakha of refa'einu in the Shemona Esrei service.  Here we submit a special petition to God to cure all the sick patients among Am Yisrael, presumably asking that they recover even before the time when the given illness would leave through natural means.  In this berakha, we address the Almighty in terms of His power to cure beyond the natural, bodily processes, to intervene supernaturally and bring a cure even before it would normally be expected.  Appropriately, we conclude this berakha by describing God not as "the Healer of all flesh," but rather as "Rofei cholei amo Yisrael" – "Healer of the sick among His nation, Israel."  This level of divine healing is reserved for amo Yisrael, His people.  As the verse states in Parashat Beshalach, observance of the mitzvot earns the reward that "all the maladies that I brought upon Egypt I will not bring upon you."  Rav Chayim Berlin explains this verse as referring to supernatural intervention to cure and prevent illness, which is granted only to Benei Yisrael, when they faithfully obey the divine command.


            This analysis of Rav Chayim Berlin found its way into a halakhic discussion by Rav Eliezer Waldenberg, in his Tzitz Eliezer (11:4).  Rav Waldenberg addresses here a case of one who used the restroom during the prayer service – let's say, for argument's sake, during the blessings of keri'at shema – and was thus not permitted to recite asher yatzar upon leaving the restroom.  Presumably, he should recite the berakha at the first opportunity he can, generally upon the conclusion of the Shemona Esrei.  However, a work entitled Benei Levi ruled that the berakha of refa'einu in Shemona Esrei fulfills one's obligation to recite asher yatzar, since both blessings speak of the Almighty's power of healing.  This is analogous to the ruling of the Peri Chadash that if one did not recite the berakha of Elokai Neshama in the morning, and remembered only after he completed the Shemona Esrei, he does not then recite Elokei Neshama, since the berakha of Mechayei Ha-meitim, which addresses the same theme of resurrection, covers this obligation.  Numerous poskim, however, including the Mishna Berura (66:23) and Chayei Adam (20:3), disagree with the view of Benei Levi, and maintain that the berakha of refa'einu does not satisfy one's obligation with respect to the berakha of asher yatzar.


            Rav Waldenberg advances numerous arguments in favor of the view of the Mishna Berura and Chayei Adam, including the aforementioned analysis of Rav Chayim Berlin.  According to Rav Chayim Berlin, these two berakhot – refa'einu and asher yatzar – speak of two distinct qualities of God, and it therefore stands to reason that one would not qualify to fulfill one's obligation with respect to the other.  On the basis of this and other factors, Rav Waldenberg sides with the position of the Mishna Berura and Chayei Adam, that a person in this case should, in fact, recite asher yatzar upon completing the Shemona Esrei.


(Taken from the compendium Ke-motzei Shalal Rav)




            Parashat Beshalach concludes with the story of Amalek's vicious and unprovoked attack against Benei Yisrael in Refidim.  In response to Amalek's offensive, Moshe summons Yehoshua and orders him to quickly draft an army and wage battle against Amalek.


            The Midrash Shemot Rabba (26) advances an intriguing explanation for why specifically Yehoshua was called upon to perform this task.  In Sefer Bereishit (42:18), we read that Yosef, by then the Egyptian viceroy, tells his brothers after their three-day imprisonment, "et ha-Elokim ani yarei" – "I am God-fearing."  Later in the Torah, in Sefer Devarim (25:18), the Torah describes Amalek at the time of their attack on Benei Yisrael as "lo yerei Elokim" – "not God-fearing."  Moshe thus told Yehoshua – a descendant of Yosef's son Efrayim – "Let the grandson of he who said, 'I am God-fearing' come and exact retribution from he about whom it is said, 'and he was not God-fearing'."


            The Midrash draws a contrast between Yosef's "God-fearing" quality and Amalek's lack of fear of God.  Wherein precisely lies the point of contrast between Yosef and Amalek?


            The answer perhaps emerges from a closer look at the contexts of the two verses cited in the Midrash.  When Yosef's brothers arrived in Egypt, desperate for grain and entirely dependent upon his good will, he was given the opportunity to avenge the mistreatment he had suffered at their hands.  What more, it appears that he had to deal harshly with them, by suspecting them of spying and thus forcing them to bring Binyamin to Egypt.  The commentators debate the question of what exactly Yosef had in mind.  The Ramban claims that Yosef felt responsible to see to the fulfillment of his dreams, which depicted all eleven brothers prostrating before him, while Abarbanel argued that he was leading them to repentance by placing them in a situation where they would have to sacrifice on Binyamin's behalf.  In a slightly different vein, one might explain that before revealing his identity to his brothers, he needed to ensure that they no longer harbored any hard feelings towards him and had truly come to regret their crime.  In any event, Yosef was in a position where he had to deal harshly with his brothers.  The human instinct of vengeance would normally lead a person in a situation such as this to exact retribution to the fullest, to ensure that the perpetrators of the crime would experience firsthand the kind of victimization he had suffered at their hands.


            Yosef, however, tells his brothers, "I am God-fearing."  He makes this remark as he prepares to inform them of his sudden change of plans: rather than keeping them all prisoners and sending one brother back to bring Binyamin, he would instead imprison just one brother and send the others back.  "God-fearing" in this context might point to Yosef's sensitivity even at a moment where he could have perhaps justified cruel treatment.  Even under such circumstances, he displayed a degree of compassion and did what he could to ease the torment to which he felt compelled to subject his brothers.


            Amalek, by contrast, acted in the precise opposite manner.  As God describes in Sefer Devarim, Amalek "surprised you along the road and cut down all those straggling behind, and you were tired and weary."  Benei Yisrael were in a position that would arouse within any ethical person a degree of compassion.  Here was a newly freed nation of former slaves traversing the searing wilderness without proper provisions.  Amalek, rather than offering assistance, capitalized on Benei Yisrael's frailty, and targeted specifically "those straggling behind," the especially weak and defenseless members of the nation.


            In this sense, Yosef's conduct towards his brothers may be seen as conversely parallel to Amalek's attack on Benei Yisrael.  Yosef, in a position that warranted a degree of mistreatment towards his brothers, found a way to mitigate the suffering they would have to endure, whereas Amalek, faced with a situation that called for compassion and sensitivity, acted with unbridled cruelty and hatred.




            The Torah tells in Parashat Beshalach of Moshe's reassurance to Benei Yisrael as they found themselves trapped between the Sea of Reeds and the pursuing Egyptian army: "Moshe said to the nation: Have no fear!  Stand in place and behold the Lord's salvation that He will perform for you this day; for as you see Egypt today – you will never again see them, ever!" (14:13).


            Chazal, in a number of places (Mekhilta; Yerushalmi, Sukka 5:1; Ester Rabba, introduction, 63), cite this verse as one of the Biblical sources for the prohibition against returning to Egypt.  The Rambam lists this prohibition as the forty-sixth mitzvat lo ta'aseh in his Sefer Ha-mitzvot, and codifies it in Hilkhot Melakhim (5:7).


            Rav Eliezer of Metz, more commonly known as the "Re'eim" or by the name of his work, Sefer Ha-yerei'im (or just "the Yerei'im"), famously imposed a remarkable restriction on this law, claiming (in siman 309) that it forbids specifically traveling from Eretz Yisrael to Egypt.  One who, let's say, sails to Egypt from a European country across the Mediterranean Sea, or who journeys northward from southern Africa to Egypt, does not violate this prohibition.  Even more remarkably, the Ritva (Yoma 38a) cites the Yerei'im as restricting this prohibition even further, claiming that even from the Land of Israel traveling to Egypt is forbidden only via the wilderness route, if one retraces the steps taken by Benei Yisrael after the Exodus.


            The Yerei'im brings proof to his surprising theory from the Gemara's discussion in Masekhet Sanhedrin (93a) of the dramatic incident of Chananya, Mishael and Azarya.  These three Jewish men (who are also referred to by their Aramaic names – Shadrakh, Meishakh and Aveid Nego) were high-ranking officials in the Babylonian government who refused to bow to an idol as the king had commanded; he sentenced them to be burned, but they miraculously emerged from the furnace unscathed.  Daniel, who also served in the Babylonian government at the time, is not mentioned in this narrative in Sefer Daniel (chapter 3).  According to one view in the Gemara, he had been sent to Egypt to purchase pigs to be bred in Babylonia.  On what basis, the Yerei'im asks, was Daniel permitted to go to Egypt?  Apparently, he reasons, Daniel was allowed to go to Egypt because he traveled there from Babylonia, rather than from Eretz Yisrael, and this thus proves that the Torah prohibition forbids only traveling to Egypt directly from the Land of Israel.


            The Gevurot Ari (Yoma 38b) objects to the Yere'im's proof in light of the Rambam's ruling (Hilkhot Melakhim 5:8), based on the Yerushalmi (Sanhedrin, end of chapter 10), that the Torah forbids only permanent residence in Egypt; going there for commercial or military purposes, the Rambam writes, is permissible.  Daniel, of course, traveled to Egypt as part of a commercial enterprise undertaken by the Babylonian empire, and thus no prohibition was involved; this Gemara therefore provides no proof to the Yerei'im's restriction of the prohibition to traveling directly from Eretz Yisrael.


            Rav Gershon Arieli, in his work Torat Ha-melekh (on the Rambam's Hilkhot Melakhim), responds to the Gevurot Ari's objection by noting that the Rambam and Yerei'im held two very different perspectives on the definition of this law forbidding a Jew from returning to Egypt.  The Yerei'im clearly felt that the Torah forbids the actual trip to Egypt, rather than residence in Egypt.  This perspective is based upon the Torah's formulation in Sefer Devarim (17:16; 28:68) that emphasizes the "derekh" – the path taken by Benei Yisrael after the Exodus.  The Rambam, by contrast, speaks in terms of residing in Egypt.  In his presentation of this halakha (Hilkhot Melakhim 5:8), he writes explicitly that it is intended to protect Benei Yisrael from the corrosive influences of ancient Egyptian civilization, which, as the Torah very clearly indicates in Sefer Vayikra (18:2), was especially decrepit.  Thus, whereas the Yerei'im defines the prohibition as forbidding the actual journey from the Land of Israel to Egypt, the Rambam views it as banning residence in Egypt.


            Clearly, then, the Yerei'im would not subscribe to the Rambam's ruling permitting a temporary visit to Egypt for commercial purposes.  From his perspective, then, Daniel's trip to Egypt could be justified only on the grounds that he traveled from Babylonia, and not from Eretz Yisrael.


            By the same token, the Yerei'im, in discussing this law, adamantly rejects the theory proposed by some that this prohibition no longer applies after the rule of the Assyrian emperor Sancheriv, who displaced the populations of all conquered lands.  (See Masekhet Yadayim 4:4; Berakhot 28a.)  Proponents of this argument claimed that the prohibition involves residence among the ancient Egyptian people, and does not relate to the geographical territory of Egypt.  For the Yerei'im, of course, this is untenable.  The Torah forbids not residence among ancient Egyptians, but rather traveling the route from Eretz Yisrael to Egypt; therefore, it remains in effect regardless of which ancient people's descendants currently live in the land of Egypt.


            In principle, we could conceive of the Rambam accepting such a theory; it should be noted, however, that he makes no mention of this point in Hilkhot Melakhim, in contrast to Hilkhot Issurei Bi'a (12:25), where he specifically writes that after Sancheriv's conquests one may marry an Egyptian convert.  (For more on this topic, see