1 Kings 11:2

Thou shalt make no covenant with them, nor with their gods.

And thou take of their daughters unto thy sons, and their daughters go a whoring after their gods, and make thy sons go a whoring after their gods.

Neither shalt thou make marriages with them; thy daughter thou shalt not give unto his son, nor his daughter shalt thou take unto thy son.

Else if ye do in any wise go back, and cleave unto the remnant of these nations, even these that remain among you, and shall make marriages with them, and go in unto them, and they to you:

Now therefore give not your daughters unto their sons, neither take their daughters unto your sons, nor seek their peace or their wealth for ever: that ye may be strong, and eat the good of the land, and leave it for an inheritance to your children for ever.

And Shechaniah the son of Jehiel, one of the sons of Elam, answered and said unto Ezra, We have trespassed against our God, and have taken strange wives of the people of the land: yet now there is hope in Israel concerning this thing. Now therefore let us make a covenant with our God to put away all the wives, and such as are born of them, according to the counsel of my lord, and of those that tremble at the commandment of our God; and let it be done according to the law. Arise; for this matter belongeth unto thee: we also will be with thee: be of good courage, and do it. Then arose Ezra, and made the chief priests, the Levites, and all Israel, to swear that they should do according to this word. And they sware. Then Ezra rose up from before the house of God, and went into the chamber of Johanan the son of Eliashib: and when he came thither, he did eat no bread, nor drink water: for he mourned because of the transgression of them that had been carried away. And they made proclamation throughout Judah and Jerusalem unto all the children of the captivity, that they should gather themselves together unto Jerusalem; And that whosoever would not come within three days, according to the counsel of the princes and the elders, all his substance should be forfeited, and himself separated from the congregation of those that had been carried away. Then all the men of Judah and Benjamin gathered themselves together unto Jerusalem within three days. It was the ninth month, on the twentieth day of the month; and all the people sat in the street of the house of God, trembling because of this matter, and for the great rain. And Ezra the priest stood up, and said unto them, Ye have transgressed, and have taken strange wives, to increase the trespass of Israel. Now therefore make confession unto the LORD God of your fathers, and do his pleasure: and separate yourselves from the people of the land, and from the strange wives. Then all the congregation answered and said with a loud voice, As thou hast said, so must we do. But the people are many, and it is a time of much rain, and we are not able to stand without, neither is this a work of one day or two: for we are many that have transgressed in this thing. Let now our rulers of all the congregation stand, and let all them which have taken strange wives in our cities come at appointed times, and with them the elders of every city, and the judges thereof, until the fierce wrath of our God for this matter be turned from us. Only Jonathan the son of Asahel and Jahaziah the son of Tikvah were employed about this matter: and Meshullam and Shabbethai the Levite helped them. And the children of the captivity did so. And Ezra the priest, with certain chief of the fathers, after the house of their fathers, and all of them by their names, were separated, and sat down in the first day of the tenth month to examine the matter. And they made an end with all the men that had taken strange wives by the first day of the first month.