Beware of practicing your righteousness before men to be noticed by them; otherwise you have no reward with your Father who is in heaven. (Matthew 6:1)
You have heard that the ancients were told, "You shall not commit murder" and "Whoever commits murder shall be liable to the court." But I say to you that everyone who is angry with his brother shall be guilty before the court; and whoever says to his brother, "You good-for-nothing," shall be guilty before the supreme court; and whoever says, "You fool," shall be guilty enough to go into the fiery hell. (verses 21-22).
You have heard that it was said, "You shall not commit adultery"; but I say to you that everyone who looks at a woman with lust for her has already committed adultery with her in his heart." (verses 27-28).