James 5:12 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 you fall into condemnation.
Jews and Arabs were notorious for swearing or taking oaths by heaven, earth, Jerusalem, the temple, the altar, and the different members of the body. Even simple affirmatives were always accompanied with an oath. It was this wicked practice that caused this command to see the light. The Greek word for condemnation here is hupokrisis which means hypocrisy. The idea is that those who were in the habit of making oaths also believed that they could make them with the mouth while the heart cancelled them. Oaths were made with mental reservations to annul them, regardless of how solemn they were. This was all done in hypocrisy and fostered searing of the conscience as to what was said. One soon became a confirmed hypocrite in such matters.
Jesus commanded us in Matthew 5:34-37 “Not to swear at all; neither by heaven; for it is God’s throne: Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. Neither shalt thou swears by thy head, because thou cannot make one hair white or black. But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these come of evil.” Don’t make any promises whatsoever, but stick to what you said you will do or not do, thus let your Yes be yes and your No be no. Our word forms part of our testimony and the enemy will do whatever necessary to discount our trustworthiness in the hope to destroy our living sacrifice (1 Pet. 2:21-23).