James 5:12 - Joseph Benson’s Commentary on the Old and New Testaments

But above all things, swear not However provoked. The Jews were notoriously guilty of common swearing, though not so much by God himself as by some of his creatures. The apostle here forbids these oaths, as well as all swearing in common conversation. It is very observable how solemnly the apostle introduces this command; above all things, swear not; as if he had said, Whatever you forget, do not forget this. This abundantly demonstrates the horrible iniquity of the crime. But he does not forbid the taking of a solemn oath before a magistrate. Neither by any other oath Namely, unlawful or unnecessary; but let your yea be yea, and your nay, nay Let your discourse be confirmed with a bare affirmation or denial; and use no higher asseverations in common discourse. But let your words stand firm; and whatever ye say, take care to make it good; lest ye fall into condemnation Expose yourselves to God's judgments.