But I say unto you, Swear not at all; neither by heaven; for it is God's throne:
Not by the earth; for it is his footstool: netherby Jerusalem; for it is the city of the great King.
Neither shalt thou swear by the head, because thou canst not make one hair white or black.
But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.

Matthew 5 chapter 34-37