Matthew 5:34-37

But I say unto you, Do not swear at all; neither by the heaven, because it is the throne of God; nor by the earth, because it is the footstool of his feet; nor by Jerusalem, because it is the city of the great King. Neither shalt thou swear by thy head, because thou canst not make one hair white or black. But let your word be Yea, yea; Nay, nay; but what is more than these is from evil.