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.

2 Corinthians 6:17
“Therefore come out from among them and be separate, says the Lord. Touch no unclean thing, and I will receive you.”

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.

1 Corinthians 5:11
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.

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! ...

2 Corinthians 7:1
Therefore, beloved, since we have these promises, let us cleanse ourselves from everything that defiles body and spirit, perfecting holiness in the fear of God.

Exodus 34:16
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 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.

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.

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.

2 Corinthians 6:14
Do not be unequally yoked with unbelievers. For what partnership can righteousness have with wickedness? Or what fellowship does light have with darkness?

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 Peter 1:14-16
As obedient children, do not conform to the passions of your former ignorance. / But just as He who called you is holy, so be holy in all you do, / for it is written: “Be holy, because I am holy.”

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.

Romans 12:2
Do not be conformed to this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what is the good, pleasing, and perfect will of God.