Matthew 5:33-35

Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: but I say unto you, Swear not at all; neither by heaven; for it is God's throne: nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King.