Read Hebrews 12:15
15 Look after each other so that none of you fails to receive the grace of God. Watch out that no poisonous root of bitterness grows up to trouble you, corrupting many. (NLT)
When he was released from prison, Nelson Mandela was asked whether he felt resentment towards those who put him there. He commented that he chose not to harbour resentment, adding that resentment was like drinking a cup of poison then sitting down and waiting for our enemy to die.
In other words, resentment doesn’t so much harm your adversary but harms you. We may relish the thought of taking revenge on those who have treated us unfairly. But in the end we only damage ourselves in the process. Our emotional arteries become silted up with hatred and bitterness. And our enemies may not even suffer hurt for all our huffing and puffing. Even if they do suffer, the satisfaction we feel is shallow and passing and unproductive.
No wonder the Bible warns us against this sort of thing. It not only corrupts us, it can be passed on to others. Bitterness on the part of one member of a Christian community can have a ripple effect on that community. Rather than chew the cud of our resentment, we are to recognise that ultimately it is God who puts things right. He is better at justice and mercy than we are.
Resentment literally means to feel all over again. For some it may be time to hit the stop button on that tape of pain that is being endlessly replayed. There are other much better feelings to be felt.