Leviticus 21:15

For I know him, that he will command his children and his household after him, and they shall keep the way of the LORD, to do justice and judgment; that the LORD may bring upon Abraham that which he hath spoken of him.

These sought their register among those that were reckoned by genealogy, but they were not found: therefore were they, as polluted, put from the priesthood.

For they have taken of their daughters for themselves, and for their sons: so that the holy seed have mingled themselves with the people of those lands: yea, the hand of the princes and rulers hath been chief in this trespass.

In those days also saw I Jews that had married wives of Ashdod, of Ammon, and of Moab: And their children spake half in the speech of Ashdod, and could not speak in the Jews' language, but according to the language of each people. And I contended with them, and cursed them, and smote certain of them, and plucked off their hair, and made them swear by God, saying, Ye shall not give your daughters unto their sons, nor take their daughters unto your sons, or for yourselves. Did not Solomon king of Israel sin by these things? yet among many nations was there no king like him, who was beloved of his God, and God made him king over all Israel: nevertheless even him did outlandish women cause to sin. Shall we then hearken unto you to do all this great evil, to transgress against our God in marrying strange wives? And one of the sons of Joiada, the son of Eliashib the high priest, was son in law to Sanballat the Horonite: therefore I chased him from me. Remember them, O my God, because they have defiled the priesthood, and the covenant of the priesthood, and of the Levites.

Judah hath dealt treacherously, and an abomination is committed in Israel and in Jerusalem; for Judah hath profaned the holiness of the LORD which he loved, and hath married the daughter of a strange god.

For if the firstfruit be holy, the lump is also holy: and if the root be holy, so are the branches.