Nehemiah 13:23-27
In those days I also saw Jews who had married women from Ashdod, Ammon, and Moab. / Half of their children spoke the language of Ashdod or of the other peoples, but could not speak the language of Judah. / I rebuked them and called down curses on them. I beat some of these men and pulled out their hair. Then I made them take an oath before God and said, “You must not give your daughters in marriage to their sons or take their daughters as wives for your sons or for yourselves! ...

Deuteronomy 7:3-4
Do not intermarry with them. Do not give your daughters to their sons or take their daughters for your sons, / because they will turn your sons away from following Me to serve other gods. Then the anger of the LORD will burn against you, and He will swiftly destroy you.

Malachi 2:11-12
Judah has broken faith; an abomination has been committed in Israel and in Jerusalem. For Judah has profaned the LORD’s beloved sanctuary by marrying the daughter of a foreign god. / As for the man who does this, may the LORD cut off from the tents of Jacob everyone who is awake and aware—even if he brings an offering to the LORD of Hosts.

1 Kings 11:1-2
King Solomon, however, loved many foreign women along with the daughter of Pharaoh—women of Moab, Ammon, Edom, and Sidon, as well as Hittite women. / These women were from the nations about which the LORD had told the Israelites, “You must not intermarry with them, for surely they will turn your hearts after their gods.” Yet Solomon clung to these women in love.

2 Corinthians 6:14-17
Do not be unequally yoked with unbelievers. For what partnership can righteousness have with wickedness? Or what fellowship does light have with darkness? / What harmony is there between Christ and Belial? Or what does a believer have in common with an unbeliever? / What agreement can exist between the temple of God and idols? For we are the temple of the living God. As God has said: “I will dwell with them and walk among them, and I will be their God, and they will be My people.” ...

Nehemiah 9:2
Those of Israelite descent separated themselves from all the foreigners, and they stood and confessed their sins and the iniquities of their fathers.

Exodus 34:15-16
Do not make a covenant with the inhabitants of the land, for when they prostitute themselves to their gods and sacrifice to them, they will invite you, and you will eat their sacrifices. / And when you take some of their daughters as brides for your sons, their daughters will prostitute themselves to their gods and cause your sons to do the same.

1 Corinthians 5:9-13
I wrote you in my letter not to associate with sexually immoral people. / I was not including the sexually immoral of this world, or the greedy and swindlers, or idolaters. In that case you would have to leave this world. / But now I am writing you not to associate with anyone who claims to be a brother but is sexually immoral or greedy, an idolater or a verbal abuser, a drunkard or a swindler. With such a man do not even eat. ...

Judges 3:5-6
Thus the Israelites continued to live among the Canaanites, Hittites, Amorites, Perizzites, Hivites, and Jebusites. / And they took the daughters of these people in marriage, gave their own daughters to their sons, and served their gods.

Nehemiah 10:28-30
“The rest of the people—the priests, Levites, gatekeepers, singers, temple servants, and all who had separated themselves from the people of the land to obey the Law of God—along with their wives and all their sons and daughters who are able to understand, / hereby join with their noble brothers and commit themselves with a sworn oath to follow the Law of God given through His servant Moses and to obey carefully all the commandments, ordinances, and statutes of the LORD our Lord. / We will not give our daughters in marriage to the people of the land, and we will not take their daughters for our sons.

1 Kings 21:25
(Surely there was never one like Ahab, who sold himself to do evil in the sight of the LORD, incited by his wife Jezebel.

2 Kings 17:33-34
They worshiped the LORD, but they also served their own gods according to the customs of the nations from which they had been carried away. / To this day they are still practicing their former customs. None of them worship the LORD or observe the statutes, ordinances, laws, and commandments that the LORD gave the descendants of Jacob, whom He named Israel.

2 Chronicles 19:2
Jehu son of Hanani the seer went out to confront him and said to King Jehoshaphat, “Should you help the wicked and love those who hate the LORD? Because of this, the wrath of the LORD is upon you.

1 Corinthians 7:12-14
To the rest I say this (I, not the Lord): If a brother has an unbelieving wife and she is willing to live with him, he must not divorce her. / And if a woman has an unbelieving husband and he is willing to live with her, she must not divorce him. / For the unbelieving husband is sanctified through his believing wife, and the unbelieving wife is sanctified through her believing husband. Otherwise your children would be unclean, but now they are holy.

Joshua 23:12-13
For if you turn away and cling to the rest of these nations that remain among you, and if you intermarry and associate with them, / know for sure that the LORD your God will no longer drive out these nations before you. Instead, they will become for you a snare and a trap, a scourge in your sides and thorns in your eyes, until you perish from this good land that the LORD your God has given you.