Intermarriage
Whether the separations Ezra demands contradict the welcome Ruth the Moabite receives.
Ezra 9:1-15
1Now when these things were done, the princes came near to me, saying, “The people of Israel, the priests, and the Levites, have not separated themselves from the peoples of the lands, following their abominations, even those of the Canaanites, the Hittites, the Perizzites, the Jebusites, the Ammonites, the Moabites, the Egyptians, and the Amorites.
2For they have taken of their daughters for themselves and for their sons, so that the holy offspring have mixed themselves with the peoples of the lands. Yes, the hand of the princes and rulers has been chief in this trespass.”
3When I heard this thing, I tore my garment and my robe, and pulled the hair out of my head and of my beard, and sat down confounded.
4Then everyone who trembled at the words of the God of Israel were assembled to me, because of their trespass of the captivity; and I sat confounded until the evening offering.
5At the evening offering I arose up from my humiliation, even with my garment and my robe torn; and I fell on my knees, and spread out my hands to Yahweh my God;
6and I said, “My God, I am ashamed and blush to lift up my face to you, my God; for our iniquities have increased over our head, and our guiltiness has grown up to the heavens.
7Since the days of our fathers we have been exceedingly guilty to this day; and for our iniquities we, our kings, and our priests, have been delivered into the hand of the kings of the lands, to the sword, to captivity, to plunder, and to confusion of face, as it is this day.
8Now for a little moment grace has been shown from Yahweh our God, to leave us a remnant to escape, and to give us a nail in his holy place, that our God may lighten our eyes, and revived us a little in our bondage.
9For we are bondservants; yet our God has not forsaken us in our bondage, but has extended loving kindness to us in the sight of the kings of Persia, to revive us, to set up the house of our God, and to repair its ruins, and to give us a wall in Judah and in Jerusalem.
10“Now, our God, what shall we say after this? For we have forsaken your commandments,
11which you have commanded by your servants the prophets, saying, ‘The land, to which you go to possess it, is an unclean land through the uncleanness of the peoples of the lands, through their abominations, which have filled it from one end to another with their filthiness.
12Now therefore don’t give your daughters to their sons. Don’t take their daughters to your sons, nor seek their peace or their prosperity forever; that you may be strong, and eat the good of the land, and leave it for an inheritance to your children forever.’
13“After all that has come on us for our evil deeds, and for our great guilt, since you, our God, have punished us less than our iniquities deserve, and have given us such a remnant,
14shall we again break your commandments, and join ourselves with the peoples that do these abominations? Wouldn’t you be angry with us until you had consumed us, so that there would be no remnant, nor any to escape?
15Yahweh, the God of Israel, you are righteous; for we are left a remnant that has escaped, as it is today. Behold, we are before you in our guiltiness; for no one can stand before you because of this.”
Ruth 4:13-17
13So Boaz took Ruth and she became his wife; and he went in to her, and Yahweh enabled her to conceive, and she bore a son.
14The women said to Naomi, “Blessed be Yahweh, who has not left you today without a near kinsman. Let his name be famous in Israel.
15He shall be to you a restorer of life and sustain you in your old age; for your daughter-in-law, who loves you, who is better to you than seven sons, has given birth to him.”
16Naomi took the child, laid him in her bosom, and became nurse to him.
17The women, her neighbors, gave him a name, saying, “A son is born to Naomi”. They named him Obed. He is the father of Jesse, the father of David.
What each tradition says
Rabbinic / Midrashic
Kohler and Jacobs state that the later conversion of Gentiles to Judaism was an important factor that essentially modified the prohibition of intermarriage. They say this conversion was believed to be typified in Ruth, when she tells Naomi, "Thy people shall be my people, and thy God my God."
Kaufmann Kohler; Joseph Jacobs, The Jewish Encyclopedia (1905), art. "Intermarriage" — Section 'Influence of Conversion'
Patristic
Chrysostom likens Ruth, of a strange race and in utmost poverty, to what belongs to us: Boaz neither despised her poverty nor abhorred her mean birth. Christ likewise received the Church, both alien and in much poverty, and took her to be partaker of great blessings.
John Chrysostom, Homilies on the Gospel of St. Matthew (Nicene and Post-Nicene Fathers, First Series, Vol. 10; George Prevost trans.) — Homily 3 (on Matthew 1:5)
Catholic
Haydock notes that some believe marriage with Canaanites, even converts, and other nations was unlawful, since Esdras ordered foreign wives sent away. But he says the context and practice of pious Hebrews show only marriage to those clinging to idolatry was forbidden, citing Salmon and Rahab, and Mahalon and Booz with Ruth.
George Leo Haydock, George Haydock's Catholic Bible Commentary (1859) — On Deuteronomy 7:3
Orthodox
No sourced position found. Checked Philaret's Longer Catechism (pravoslavieto.com) — no passage commentary on Ezra or Ruth; an archive.org search for a public-domain English Theophylact or Euthymius Zigabenus commentary on the historical books found only Greek, Latin, and German editions. No PD English Eastern treatment of the Ezra/Ruth question located.
Reformed / Protestant
Gill reads Deuteronomy 23:3 as forbidding an Ammonite or Moabite man to marry an Israelite woman. He notes the Jews restrained this to males, since the text says Ammonite not Ammonitess, Moabite not Moabitess. They allowed females of those nations to marry Israelites if they were proselytesses, as Ruth was.
John Gill, John Gill's Exposition of the Whole Bible — On Deuteronomy 23:3
Evangelical
Wesley says Ruth could be taken, though a Moabite, because the prohibition against marrying such people is limited to those who continue heathens. Ruth was a sincere proselyte and convert to the God of Israel. He adds that whoever forsakes all for Christ will find more than all with him.
John Wesley, Explanatory Notes upon the Old Testament — Note on Ruth 4:13