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.

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.

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.

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.

Nehemiah 13:25-27
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! / Did not King Solomon of Israel sin in matters like this? There was not a king like him among many nations, and he was loved by his God, who made him king over all Israel—yet foreign women drew him into sin. / Must we now hear that you too are doing all this terrible evil and acting unfaithfully against our God by marrying foreign women?”

Ezra 9:1-2
After these things had been accomplished, the leaders approached me and said, “The people of Israel, including the priests and Levites, have not kept themselves separate from the surrounding peoples whose abominations are like those of the Canaanites, Hittites, Perizzites, Jebusites, Ammonites, Moabites, Egyptians, and Amorites. / Indeed, the Israelites have taken some of their daughters as wives for themselves and their sons, so that the holy seed has been mixed with the people of the land. And the leaders and officials have taken the lead in this unfaithfulness!”

Deuteronomy 20:17-18
For you must devote them to complete destruction—the Hittites, Amorites, Canaanites, Perizzites, Hivites, and Jebusites—as the LORD your God has commanded you, / so that they cannot teach you to do all the detestable things they do for their gods, and so cause you to sin against the LORD your God.

Psalm 106:34-36
They did not destroy the peoples as the LORD had commanded them, / but they mingled with the nations and adopted their customs. / They worshiped their idols, which became a snare to them.

1 Corinthians 7:39
A wife is bound to her husband as long as he lives. But if her husband dies, she is free to marry anyone she wishes, as long as he belongs to the Lord.

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.” ...

Malachi 2:11
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.

1 Kings 16:31-33
And as if it were not enough for him to walk in the sins of Jeroboam son of Nebat, he even married Jezebel the daughter of Ethbaal king of the Sidonians, and he then proceeded to serve and worship Baal. / First, Ahab set up an altar for Baal in the temple of Baal that he had built in Samaria. / Then he set up an Asherah pole. Thus Ahab did more to provoke the LORD, the God of Israel, to anger than all the kings of Israel before him.

1 Corinthians 10:20-22
No, but the sacrifices of pagans are offered to demons, not to God. And I do not want you to be participants with demons. / You cannot drink the cup of the Lord and the cup of demons too; you cannot partake in the table of the Lord and the table of demons too. / Are we trying to provoke the Lord to jealousy? Are we stronger than He?

2 Kings 17:7-8
All this happened because the people of Israel had sinned against the LORD their God, who had brought them out of the land of Egypt from under the hand of Pharaoh king of Egypt. They had worshiped other gods / and walked in the customs of the nations that the LORD had driven out before the Israelites, as well as in the practices introduced by the kings of Israel.

Hosea 4:12-14
My people consult their wooden idols, and their divining rods inform them. For a spirit of prostitution leads them astray and they have played the harlot against their God. / They sacrifice on the mountaintops and burn offerings on the hills, under oak, poplar, and terebinth, because their shade is pleasant. And so your daughters turn to prostitution and your daughters-in-law to adultery. / I will not punish your daughters when they prostitute themselves, nor your daughters-in-law when they commit adultery. For the men themselves go off with prostitutes and offer sacrifices with shrine prostitutes. So a people without understanding will come to ruin.