"You have heard that it was said to those of old, 'You shall not murder, and whoever murders will be in danger of the judgment.' But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, 'Raca!' shall be in danger of the council. But whoever says, 'You fool!' shall be in danger of hell fire." (Matt. 5:21-22) "Whoever hates his brother is a murderer, and you know that no murderer has eternal life abiding in him." (1 John 3:15)

It is said that a rattlesnake, if cornered, will sometimes become so upset that it will bite itself. That is exactly what the harboring of hate and resentment against others is - a biting of oneself. We think that we are harming others in holding these grudges and hates, but the deeper harm is to ourselves. (From 1500 Illustrations for Biblical Preaching, p. 180)