Boundaries of Jewish Identity: Who is in and who is out?

(9) You stand this day, all of you, before the LORD your God: your tribal heads, your elders, and your officials, all the men of Israel, (10) your children, your wives, and even the stranger within your camp, from the woodchopper to water drawer— (11) to enter into the covenant of the LORD your God—which the LORD your God is concluding with you this day, with its sanctions; (12) to the end that He may establish you this day as His people, and be your God, as He promised you and as He swore to your fathers, to Abraham, to Isaac, and to Jacob. (13) I make this covenant, with its sanctions, not with you alone, (14) but with both those who are standing here with us this day before the LORD our God, and with those who are not here with us this day.

(5) "It would be a favor to us," they continued, "if this land were given to your servants as a holding; do not move us over the Jordan." (6) Moses replied to the Gadites and to the Reubenites, "Are your brothers to go to the war while you stay here?"

(16) Then they stepped up to him and said, "We will build here sheepfolds for our flocks, and towns for our children. (17) And we will hasten as shock-troops in the van of the Israelites until we have established them in their home, while our children stay in the fortified towns because of the inhabitants of the land. (18) We will not return to our homes, until every one of the Israelites is in possession of his portion. (19) But we will not have a share with them in the territories beyond the Jordan, for we have received our share on the east side of the Jordan." (20) Moses said to them: "If you do this, if you go to battle as shock-troops, at the instance of the LORD,... (23) this land shall be your holding under the Lord."

(16) But Ruth replied: "Do not urge me to leave you, to turn back and not follow you. For wherever you go, I will go; wherever you lodge, I will lodge; your people shall be my people, and your God my God."

(2) Then Shecaniah the son of Jehiel, of the family of Elam spoke up and said to Ezra, "We have trespassed against our God, by bringing into our homes foreign women from the peoples of land; but there is still hope for Israel despite this. (3) Now then, let us make a covenant with our God to expell all these women, and who have born to them, in accordance with the bidding of the Lord and of all who are concerned over the commandment of our God; and let the Teaching be obeyed.

(4) On that very day, Yehuda, an Ammonite convert, came and stood before them in the Beit Midrash, and said to them, "What is my status with regard to whether I can enter [via marriage] into the congregation [of Israel]?" Rabban Gamliel said to him, "You are prohibited." Rabbi Yehoshua said to him, "You are permitted." Rabban Gamliel said to him, "The verse says, (Deuteronomy 23:4) 'An Ammonite and a Moavite may not enter into the congregation of the Lord, even to the tenth generation,' and so forth." Rabbi Yehoshua said to him, "And are the Ammonites or Moavites still [dwelling] in their own place? Sancheriv, king of Assyria, already arose and blended all the nations, as the verse says, (Isaiah 10:13) 'I have removed the borders of nations, and I have plundered their treasures, and like a great warrior laid low the inhabitants.'" Rabban Gamliel said to him, "The verse [also] states, (Jeremiah 49:6) 'And afterwards I shall return the captives of the children of Ammon,' and they are already returned." Rabbi Yehoshua said to him, "The verse [also] states, (Amos 9:14) 'And I shall return the captives of my nation Israel,' [and Judah], and they are not yet returned." They [the Sages, subsequently] permitted him [the Ammonite convert] to enter into the congregation.

..Israel hath sinned (Joshua 7:11). R. Abba b. Zabda said, "Even though [the people] have sinned, they are still [called] 'Israel'. R. Abba said: Thus people say, A myrtle, though it stands among reeds, is still a myrtle, and it is so called..