Matthew 5:37 in the World English Bible
But let your ‘Yes’ be ‘Yes’ and your ‘No’ be ‘No.’ Whatever is more than these is of the evil one.
Context
36 Neither shalt thou swear by thy head, because thou canst not make one hair white or black.
37 But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.
38 Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth: