Matthew 5:21-22

"You have heard that our fathers were told, `Do not murder,'l and that anyone who commits murder will be subject to judgment.

But I tell you that anyone who nurses anger against his brother will be subject to judgment; that whoever calls his brother, `You good-for-nothing!' will be brought before the Sanhedrin; that whoever says, `Fool!' incurs the penalty of burning in the fire of Gei-Hinnom!