Matthew Henry Commentary 2 Corinthians 6:11-18

"Our mouth is open unto you, O Corinthians, our heart is enlarged. Ye are not straitened in us, but ye are straitened in your own affections. Now for a recompense in like kind (I speak as unto [my] children), be ye also enlarged. Be not unequally yoked with unbelievers: for what fellowship have righteousness and iniquity? or what communion hath light with darkness? And what concord hath Christ with Belial? or what portion hath a believer with an unbeliever? And what agreement hath a temple of God with idols? for we are a temple of the living God; even as God said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people. Wherefore Come ye out from among them, and be ye separate, saith the Lord, And touch no unclean thing; And I will receive you, And will be to you a Father, And ye shall be to me sons and daughters, saith the Lord Almighty." — 2 Corinthians 6:11-18 (ASV)

It is wrong for believers to associate with the wicked and profane. The word unbeliever applies to all who are lacking true faith. True pastors will caution their beloved children in the gospel not to be unequally yoked. The fatal effects of neglecting Scripture's instructions concerning marriage clearly appear.

Instead of a help meet, the union brings a snare. Those whose cross it is to be unequally united, without their willful fault, may expect consolation under it; but when believers enter into such unions, against the express warnings of God's word, they must expect much distress. The caution also extends to everyday associations.

We should not join in friendship and acquaintance with wicked men and unbelievers. Although we cannot entirely avoid seeing, hearing, and being with such people, we should never choose them as friends. We must not defile ourselves by fellowship with those who defile themselves with sin. Come out from the workers of iniquity, and separate from their vain and sinful pleasures and pursuits; from all conformity to the corruptions of this present evil world.

If it is an envied privilege to be the son or daughter of an earthly prince, who can express the dignity and happiness of being sons and daughters of the Almighty?