Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, “Vengeance is mine, I will repay, says the Lord.” (Romans 12:19)

Why is this such a crucial promise in overcoming our bent toward bitterness and revenge? The reason is that this promise answers one of the most powerful impulses behind anger — an impulse that is not entirely wrong.

In many cases, real wrongs have been done to us. Therefore, it is not entirely wrong to feel that justice should be done. What’s wrong is to feel that we must make it happen and that we may feel bitter until it does. This would be a deadly mistake.

During my seminary days, Noël and I were in a small group for couples that began to relate at a fairly deep personal level. One evening we were discussing forgiveness and anger. One of the young wives said that she could not and would not forgive her mother for something she had done to her as a young girl.

We talked about some of the biblical commands and warnings concerning an unforgiving spirit.

• Be kind to one another, tenderhearted, forgiving one another, as God in Christ forgave you. (Ephesians 4:32)

• If you do not forgive others . . . neither will your Father forgive your trespasses. (Matthew 6:15)

But she would not budge. So I warned her that her very soul was in danger if she kept on with such an attitude of unforgiving bitterness. But she was adamant that she would not forgive her mother.

The grace of God’s judgment is promised to us here in Romans 12 as a means of helping us overcome such a deadly spirit of revenge and bitterness.

Paul’s argument is that we can be sure that all wrongs will be dealt with by God and that we can leave the matter in his hands because vengeance belongs to the Lord. To motivate us to lay down our vengeful desires he gives us a promise: “I will repay, says the Lord.”

The promise that frees us from an unforgiving, bitter, vengeful spirit is the promise that God will settle our accounts. He will do it more justly and mercifully and more thoroughly than we ever could. He punishes all sin. Nobody gets away with anything. He punishes it either in Christ on the cross for those who repent and trust him, or in hell for those who don’t. Therefore, we can back off and leave room for God to do his perfect work.