Matthew 5:33-37

33 Again you have heard that it was said to them of old, thou shalt not forswear thyself: but thou shalt perform thy oaths to the Lord.

34 But I say to you not to swear at all, neither by heaven for it is the throne of God:

35 Nor by the earth, for it is his footstool: nor by Jerusalem, for it is the city of the great king:

36 Neither shalt thou swear by thy head, because thou canst not make one hair white or black.

37 But let your speech be yea, yea: no, no: and that which is over and above these, is of evil.