James 5:12 - Coke's Commentary on the Holy Bible

But above all things—swear not,— Some consider this verse as joined to what goes before, to intimate that they were to be aware of impatience, and particularly as it might lead them into rash and profane swearing, as men in a passion are more apt to swear. The δε, but, favours this connection; though as the word δε is often used by way of transition only, and this has so much the air of a general rule, it may well be considered as such, and as distinct from the rest. They were not to swear profanely at any time, either in affliction or prosperity; and accordingly the apostle here very strongly condemns the vice in general. When he says, Above or before all things, swear not, it is not to be supposed that he reckons this as the greatest of all crimes; but he condemns it in an earnest manner, as one very great vice to which the Jews were remarkably addicted, and as a horrid habit which required much care and attention to shake it off. See what has been said on this subject, Matthew 5:33-37.