Nehemiah 10:30
and that we will not give our daughters [as wives] to the peoples of the land or take their daughters for our sons.
Exodus 34:16
and you might take some of his daughters for your sons, and his daughters would play the prostitute with their gods and cause your sons also to play the prostitute (commit apostasy) with their gods [that is, abandon the true God for man-made idols].
Deuteronomy 7:3
You shall not intermarry with them; you shall not give your daughter to his son, nor shall you take his daughter for your son;
Ezra 9:1-3
When these things were completed, the officials came to me and said, “The people of Israel and the priests and Levites have not separated themselves from the peoples of the lands, but have committed the repulsive acts of the Canaanites, Hittites, Perizzites, Jebusites, Ammonites, Moabites, Egyptians, and Amorites.
Ezra 9:12-14
So now do not give your daughters to their sons or take their daughters for your sons; and never seek their peace or their prosperity, so that you may be strong and eat the good things of the land and leave it as an inheritance to your children forever.’
Ezra 10:10-12
Then Ezra the priest stood up and said to them, “You have been unfaithful [to God] and have married foreign (pagan) women, adding to the guilt of Israel.