Is there someone that you need to forgive? It may be for something that they did yesterday or twenty years ago. Genuine forgiveness is rare in our current “cancel culture”, where revenge or retaliation is more often the case. But Tim Keller in his excellent book Forgive: Why Should I and How Can I? tells us that God requires forgiveness whether or not the offender has repented and has asked for forgiveness.
Keller tells us that forgiveness is always costly. It is a form of voluntary suffering. In forgiving, rather than retaliating, we make a choice to bear the cost. However, he tells us that the self-centeredness that grows when we stay angry at somebody, when we hold things against them, when we continue to regard them as if they’re liable to us and they owe us, is a prison. Keller tells us that if we don’t forgive the person, we will likely veer into the territory of revenge.

Keller tells us that human forgiveness must be based on an experience of divine forgiveness, and that the concept of forgiveness is central to the meaning of the Bible. He tells us that divine mercy should change our hearts so that we are able to forgive as God forgave us. If we will not offer others forgiveness, it may reflect that we did not truly repent and receive God’s forgiveness.
Think of that person who has hurt, betrayed or offended you. By forgiving them, you give up the desire to get even. Keller tells us that to forgive them is to give them a gift they do not in any way deserve. Instead, in love, you are absorbing the debt that they owe you, and you are truly walking in Christ’s footsteps.
Keller tells us that real forgiveness always hopes for a full restoration of the offender and the relationship. He writes that a Christian is responsible to begin the process of reconciliation, regardless of how the alienation began. Almost always reconciliation is best done by both repenting and forgiving—by both admitting your own wrong and pointing out the wrong of the other. Keller tells us that only the gospel prepares you for both sides of the Christian reconciliation model. It humbles you enough to make you able to be a forgiver and, at the same time, affirms and fills you with such a sense of worth and love that it makes you able to be a repenter.
Keller tells us that forgiveness is a gift given by a sinner saved by sheer grace to another. It means giving up the right to revenge, the right to seek repayment from the one who harmed you. If we remain unforgiving, Keller tells us that this may mean that we remain unaware of our own need for forgiveness.

Yes, forgiveness is costly. It is counter-cultural. Is there someone you need to forgive? Keller’s book provides detailed instructions on how to forgive and seek reconciliation. Pursue forgiveness, walk in Christ’s footsteps, just like He has forgiven us:
For I will be merciful toward their iniquities,
and I will remember their sins no more.    Hebrews 8:12