Jesus said to his disciples: “You have heard that it was said to your ancestors, Do not take a false oath, but make good to the Lord all that you vow. But I say to you, do not swear at all…” Matthew 5:33–34
When the Pharisees with some scribes who had come from Jerusalem gathered around Jesus, they observed that some of his disciples ate their meals with unclean, that is, unwashed, hands. Mark 7:6–8