But let your speech be, Yea, yea; Nay, nay: and whatsoever is more than these is of the evil one.
Profane swearing is always the mark of a depraved heart. When a man swears, it signals he knows he will not be believed otherwise; and indeed, the swearer is seldom trusted. The man whose simple word suffices, whose character is spotless in all things, needs no oaths.
AI summary
But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil. (t) Whatever you affirm, affirm it alone, and whatever you deny, deny it alone without any more words. (u) From an evil conscience, or from the devil.
Perjury is impiety toward God and injustice toward man combined; it renders a man obnoxious to divine wrath. The ancients understood this so well they turned their swearing formulas into curses upon themselves, wishing God's judgment if they lied. This shows how deeply nations have always felt that God must curse the false swearer, if He be God.
AI summary
Commenting on Matthew 5:33-37