Albert Barnes Commentary 2 Corinthians 6:15

"And what concord hath Christ with Belial? or what portion hath a believer with an unbeliever?" — 2 Corinthians 6:15 (ASV)

And what concord. sumphōnēsis. Sympathy; unison. This word refers, properly, to the unison or harmony produced by musical instruments, where there is a chord. What accordance or unison is there? What strings, when struck, will produce a chord of harmony? The idea, then, is that there is as much discord between Christ and Belial as there is between musical instruments that produce only discordant and jarring sounds.

Has Christ. What does Christ have in common with Belial? This question implies that Christians are governed by the principles of Christ and follow His example.

Belial. This is Belial, or Beliar, as it is found in some later editions. The form Beliar is Syriac. The Hebrew word for it literally means without profit, worthlessness, or wickedness. It is evidently applied here to Satan. The Syriac version translates it as "Satan."

The idea is that the people to whom Paul referred—the heathen, wicked, unbelieving world—were governed by the principles of Satan and were taken captive by him at his will (2 Timothy 2:26). Christians should be separate from the wicked world, just as Christ was separate from all the feelings, purposes, and plans of Satan. Christ had no participation in them and formed no union with them; and so it should be with the followers of Christ in relation to the followers of Satan.

Or what part. meris. Portion, share, participation, fellowship. This word usually refers to a division of an estate (Luke 10:42).

There is no participation, nothing in common.

He that believes. A Christian; a man whose characteristic is that he believes in the Lord Jesus.

With an infidel. This refers to a man who does not believe—whether a heathen idolater, a profane man, a scoffer, a philosopher, a man of science, a moral man, or a person devoted to worldly pleasures. The idea is that, on the subject of religion, there is no union, nothing in common, no participation between a believer and such a person.

They are governed by different principles, have different feelings, are looking to different rewards, and are tending to a different destiny. The believer, therefore, should not select his partner in life and his chosen companions and friends from this class, but from those with whom he has sympathy, and with whom he has common feelings and hopes.