This was said Exodus 20:7, and more plainly Leviticus 19:12; the substance was there said, though the words be not verbatim recited.
Related Commentaries of Matthew 5:33
Matthew 5:33
33 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: