From Dallas Willard in The Divine Conspiracy:
Contemptuous actions and attitudes are a knife in the heart that permanently harms and mutilates peoples souls. That they are common does not ease their destructiveness, (pgs. 152-153).
Why is it that contemptuous actions and attitudes are so prevalent in the church? Why don’t we challenge this more aggressively? Jesus calls this attitude of the heart as the moral equivalent to murder.
“You have heard that it was said to those of old, ‘You shall not murder; and whoever murders will be liable to judgment.’ But I say to you that everyone who is angry with his brother will be liable to judgment; whoever insults his brother will be liable to the council; and whoever says, ‘You fool!’ will be liable to the hell of fire, (Matthew 5:21-22, ESV).
Anger, for many of us, is not a righteous thing, but rather prideful or vengeful and it seeks to do harm. God throughout the Bible pointed His anger at sin. Righteous anger is anger at injustice and sin. Not at sinners, and not just when we are sinned against which is usually the only time we are angry at sin.
Righteous anger on our parts should lead to a response that is graceful and is bathed in truth. We should demonstrate mercy to the victims, and seek reconciliation with those who offend.
Worldly anger leads to contempt which destroys spiritually, emotionally, relationally, and even physically when taken to the fullest degree. It never pleases God, and should not be present in the life of a follower of Christ.
But it often is.