Midrash sur Chroniques 1 2:17

Regarding that which the verse states: “Shaḥarayim begot children in the field of Moav [after he had sent them away, Ḥushim and Baara his wives]” (I Chronicles 8:8), Elijah, of blessed memory, asked Rabbi Nehorai, he said to him: ‘What is this that is written: “Shaḥarayim begot in the field of Moav”?’ [Rabbi Nehorai] said to him: ‘A great man begot in the field of Moav.’ “After he had sent them away” (I Chronicles 8:8) – as they were from the tribe of Benjamin, as it is written: “The tribes of Israel sent men through all the tribe of Benjamin, saying” (Judges 20:12).¹⁴³Just as the term “sent” appears in Judges regarding the tribe of Benjamin, the verse in Chronicles is hinting to the fact that the man’s wives were from the tribe of Benjamin.
Another interpretation, “Shaḥarayim,” this is Boaz. Why was his name called Shaḥarayim? It is because he was free [meshuḥrar] of iniquities. “Begot in the field of Moav,” as he begot from Ruth the Moavite. “After he had sent them away,” as he was from the tribe of Judah, as it is stated: “And he sent Judah before him to Joseph” (Genesis 46:28). “Ḥushim and Baara his wives,” does a man beget his wives? Rather, he was swift like a leopard and articulated the halakha:¹⁴⁴He expounded the verse: “An Amonite and a Moavite shall not enter the congregation of the Lord” (Deuteronomy 23:4). An Amonite but not an Amonite woman, a Moavite but not a Moavite woman. “He begot from Ḥodesh his wife” (I Chronicles 8:9) – it should have stated only, “from Baara his wife.” Rather, in his days, the halakha of an Amonite but not an Amonite woman, a Moavite and not a Moavite woman, was introduced [nitḥadsha].
One verse says: “Yitra the Ishmaelite” (see I Chronicles 2:17), and one verse says: “Yitra the Israelite” (II Samuel 17:25). Rabbi Yehoshua ben Levi said: He is Yitra the Ishmaelite, he is Yitra the Israelite.¹⁴⁵Both verses refer to the same person. Rabbi Shmuel bar Naḥman and the Rabbis: Rabbi Shmuel said: He was an Ishmaelite, and you say Israelite? Rather, he was an Ishmaelite. He entered the study hall and found Yishai sitting and expounding thus: “Look to Me, and be saved, all the ends of the earth…” (Isaiah 45:22).¹⁴⁶Anyone from all the ends of the earth can look to God and be saved. He converted, and [Yishai] gave him his daughter. The Rabbis say: He was an Israelite, and you say Ishmaelite? Rather, he was an Israelite and he girded his sword like an Ishmaelite. He stuck his sword in the middle of the study hall and said: I will either kill or be killed until I establish the halakha for the multitudes, so that anyone who abrogates this halakha, I will behead him with this sword: An Amonite but not an Amonite woman, a Moavite and not a Moavite woman.

GEMARA: Whence do we learn that (that females are permitted)? R. Jochanan said: From the following passage (I Sam. 17, 55) And when Saul saw David going forth against the Philistine, he said unto Abner, the captain of the army; 'Abner, whose son is this lad?' And Abner said: 'As thy soul liveth, O king, I know it not.' Was it then the fact that he (Saul) did not know him? Behold it is written (Ib. 16, 21) And he (Saul) loved him greatly, and he became his armour-bearer. Shall we assume that his question was regarding David's father? Then our question is: Was he then not known to Saul? Behold it is written (Ib. 17, 12) And the man was old in the days of Saul, belonging to the persons [of high esteem,] whereupon Rab, and according to others R. Abba said: This refers to Jesse, David's father, who came in with the army and went out with the army." [Hence Jesse was well known to Saul.] We must therefore say that Saul thus said unto Abner: "Go and ask whether David is the descendant of Perez or of Zerach. If he is the offspring of Perez, then he is destined to royalty, and a king may break through fences [to cut a way through for his army,] against which no one has the right to protest; but if he is of the progeny of Zerach, then he will merely rise to eminence." But what caused Saul bid Abner to ask of David's origin? Because of his garments, concerning which it is written (Ib., ib., 38) And Saul clothed David with his garments (madav). Why is madav used here? This means that his (Saul's) garments were such as fitted David's stature, although it is written (Ib. 10, 23) And he (Saul) was higher than any of the people from his shoulder and upward. [Saul then said to himself:] "What does this fact that my garments fit him signify? Surely he is destined to become the king." To which Doeg the Adamian remarked: "Before you begin an inquiry as to his fitness to the royalty or not, inquire rather whether he is fit to enter the congregation (to inter-marry with Israelites), because he is of the seed of Ruth the Moabite." Thereupon Abner said to him: "We are taught in a Mishnah: A converted male-Ammouite [is excluded from intermarrying] with Judaeans, but not a female; a converted male-Mo'abite, but not a female." According to your interpretation," remarked Saul, "then in the case of a Mamzer also say that a male is prohibited from entering the congregation but not a female?" "The passage says Mamzer, [which means] anything repulsive, including both sexes." Concerning the Egyptians, let us say also that only male Egyptians are mentioned but not females!" "Here [concerning the Ammonites and Mo'abites] it is different, because the reason [of the restriction] is given in the Torah (Deut. 23, 5) For the reason, that they met you not with bread and with water. The custom is for men to meet with bread and wine, but not for women to meet." Nevertheless the men should have met the Israelites and the women the Israelitish woman [hence the reason is for both]. Thereupon Abner remained silent [and was not able to answer this refutation.] Soon after this (I Sam. 17, 56) And the king said: Ask thou whose son this youth is. Why in the first place call David Na'ar (lad), and then call him elem (youth)? Thus did Saul say to Abner: "This law is concealed from thee, go therefore and inquire in the academy." He finally made inquiry, and they told him: "An Ammonite but not an Ammonitish woman, a Moabite, but not a Moamitish woman." (Fol. 77) Doeg raised all the above objections, which silenced them, [causing them to reverse their decisions,] and they were about to announce that he (David) was not fit to be in the congregation of Israel. Immediately after this [the passage says] (II Sam. 17, 25) And Amassa was the son of a man, whose name was Yithra the Israelite, who had gone into Abigail the daughter of Nachash, etc. And it is written (I Chr. 2, 17) And the father of Amassa was Jether the Ishmaelite, whereupon Raba said: Infer from this that Jether tied a sword around him like an Ishmaelite and said: 'Whoever will not obey this decision shall be stabbed with a sword, for thus have I a tradition from the court of Samuel of Ramathaim: An Ammonite, but not an Ammonitish woman; a Moabite, but not a Moabitish woman.' " But how can such evidence be relied upon? Has not R. Abba said in the name of Rab: "A scholar that renders a decision [concerning a disputed question,] if he rendered the decision prior to the incident he is to be heeded, but not otherwise." Here it is different, because Samuel [the prophet] and his court were then still in existence [and could thus be easily verified.] However, what about the above objection? Here (in Babylon) it was explained because (Ps. 45, 14) All gloriously attired awaited the king's daughter in the inner chamber, [hence the women are exempt from outside duty.] In the Land of Israel, it was inferred, and according to some, R. Isaac said: From the following passage (Gen. 18, 9) And they said unto him where is Sarah thy wife? etc. [Hence the women were exempt from the duty of meeting Israel.]