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 particularly 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 a solemn oath before a magistrate. Let your yea be yea; and your nay, nay — Use no higher asseverations in common discourse; and let your word stand firm. Whatever ye say, take care to make it good.
Related Commentaries of James 5:12
James 5:12
12 But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and your nay, nay; lest ye fall into condemnation.