(2) they approached Zerubbabel and the chiefs of the clans and said to them, “Let us build with you, since we too worship your God, having offered sacrifices to Him since the time of King Esarhaddon of Assyria, who brought us here.” (3) Zerubbabel, Jeshua, and the rest of the chiefs of the clans of Israel answered them, “It is not for you and us to build a House to our God, but we alone will build it to Adonai God of Israel, in accord with the charge that the king, King Cyrus of Persia, laid upon us.”
(2) Those of the stock of Israel separated themselves from all foreigners, and stood and confessed their sins and the iniquities of their fathers.
Baba Kamma 38a
But isn’t it taught in a baraita that Rabbi Meir says: From where is it derived that even a gentile who engages in Torah is considered like a High Priest? The verse states with regard to the mitzvot: “Which if a person does, he shall live by them” (Leviticus 18:5). It is not stated: Which if priests and Levites and Israelites do, they shall live by them, but rather: A person, indicating that all people are included. You have therefore learned that even a gentile who engages in Torah study is considered like a High Priest.
Tiferet Yisrael on Avot 3:14
Even if our sages had not explicitly taught (that righteous Gentiles have a place in the World to Come) we would have understood this ourselves since God is righteous in all [of God's] ways … and we see many of the righteous Gentiles who not only recognize the Creator and believe in the divine origin of the Torah and also act charitably