MT 5:20-26 
Jesus said to his disciples:  "I tell you, unless your morality surpasses that of the scribes and Pharisees, you will not enter into the Kingdom of heaven.  "You have heard that it was said to your ancestors, You shall not kill; and whoever kills will be liable to judgment. But I say to you, whoever is angry with his brother will be liable to judgment, and whoever says to his brother, 'Raqa,' will be answerable to the Sanhedrin, and whoever says, 'You fool,' will be liable to fiery Gehenna. Therefore, if you bring your gift to the altar, and there recall that your brother has anything against you, leave your gift there at the altar, go first and be reconciled with your brother, and then come and offer your gift. Settle with your adversary quickly while on the way to court with him.