While pondering scriptures about being careful with our words--Mat 12:36ff this passage came to mind....
Teaching about Anger
21 “You have heard that our ancestors were told, ‘You must not murder. If you commit murder, you are subject to judgment.’[c] 22 But I say, if you are even angry with someone,[d] you are subject to judgment! If you call someone an idiot,[e] you are in danger of being brought before the court. And if you curse someone,[f] you are in danger of the fires of hell.[g