2 Corinthians 6:14 Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness? What accord has Christ with Belial? Or what portion does a believer share with an unbeliever?
Nehemiah 13:23-26 In those days also I saw the Jews who had married women of Ashdod, Ammon, and Moab. And half of their children spoke the language of Ashdod, and they could not speak the language of Judah, but only the language of each people. And I confronted them and cursed them and beat some of them and pulled out their hair. And I made them take an oath in the name of God, saying, “You shall not give your daughters to their sons, or take their daughters for your sons or for yourselves. Did not Solomon king of Israel sin on account of such women? Among the many nations there was no king like him, and he was beloved by his God, and God made him king over all Israel. Nevertheless, foreign women made even him to sin.
Psalms 106:35 but they mixed with the nations and learned to do as they did.
Proverbs 22:24 Make no friendship with a man given to anger, nor go with a wrathful man,
1 Corinthians 15:33 Do not be deceived: “Bad company ruins good morals.”
1 Corinthians 10:21 You cannot drink the cup of the Lord and the cup of demons. You cannot partake of the table of the Lord and the table of demons.
James 4:4 You adulterous people! Do you not know that friendship with the world is enmity with God? Therefore whoever wishes to be a friend of the world makes himself an enemy of God.
Proverbs 29:27 An unjust man is an abomination to the righteous, but one whose way is straight is an abomination to the wicked.
Ephesians 5: 6 Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience. Therefore do not become partners with them; for at one time you were darkness, but now you are light in the Lord. Walk as children of light (for the fruit of light is found in all that is good and right and true), and try to discern what is pleasing to the Lord. Take no part in the unfruitful works of darkness, but instead expose them.
Paul is speaking to the overly broad affections of the Corinthian Christians. They had joined themselves to unbelievers.
Unequally yoked – How can we do this? Certainly by marrying an unbeliever, which is the most common way this principle is applied. “A very wise and very holy man was given his judgment on this point: ‘A man who is truly pious, marrying with an unconverted woman, will either draw back to perdition, or have a cross during life.’ The same may be said of a pious woman marrying an unconverted man. Such persons cannot say this petition of the Lord’s prayer, Lead us not into temptation. They plunge into it of their own accord.” (Clarke)
However, Paul means much more here than only marrying an unbeliever. It really applies to any environment where we let the world influence our thinking. When we are being conformed to this world and are not being transformed by the renewing of your mind (Romans 12:2), we join together with unbelievers in an ungodly way.
This speaks especially to the issue of influence. Paul is not suggesting that Christians never associate with unbelievers (he makes this clear in 1 Corinthians 5:9-13). The principle is that we are to be in the world, but not of the world, like a ship should be in the water, but water shouldn’t be in the ship. If the world is influencing us, it is clear we are unequally yoked together with unbelievers. And this unequal yoke, or ungodly influence, may come through a book, a movie, a television show, a magazine, or even through worldly Christian friends. Most Christians are far too indiscriminate about the things they allow to influence their minds and lives. We all like to believe that we can be around ungodly things as much as we want and that we are strong enough to ward off the influence. But we must take seriously the words of Scripture: Do not be deceived: “Evil company corrupts good habits” (1 Corinthians 15:33). It needs to come back to the simple question from Romans 12:2: Are we being conformed to this world, or are we being transformed by the renewing of your mind?