In Matthew 18, Peter asked the Lord how often one has to forgive another person. Would seven times be sufficient? Christ responded not seven, but 77 times.

In Genesis there is an interesting, but little known story about one of Cain's descendants, Lamech. Cain, who had killed his brother Abel, was barred from society (today we do that with prison), but also his life was protected by God, who said whoever kills Cain will be avenged seven times.

Cain later even had a family. Lamech is five generations down from Cain. He composed the so called Song of the Sword in Genesis 4:23-24 (NRSV):

“Lamech said to his wives: ‘Adah and Zillah, hear my voice; you wives of Lamech, listen to what I say: I have killed a man for wounding me, a young man for striking me. If Cain is avenged sevenfold, truly Lamech seventy-sevenfold.’”

I wonder whether it is coincidence that the numbers for forgiveness in Mt 18 and for avenging a murderer are the same: seven times and 77 times.

However, the thought is, of course, not to count at all.

Those numbers try to illustrate that there is no limit, neither for God's vengeance for anybody who hurts one he has forgiven already, nor for our own willingness to forgive.

In Leviticus 19:18, the verse that Jesus quoted regarding the highest commandment, we also read: “You shall not take vengeance, or bear a grudge against any of your people, but you shall love your neighbour as yourself: I am the Lord.”

Thus, to love your neighbour means to forgive.

Revenge and forgiveness are closely related. It is human to want revenge when we are wronged.

If somebody hurts me, the initial, instinctive reaction is to beat back. In the Sermon on the Mount, Jesus talked about revenge and forgiveness several times. One of those lessons says:

“You have heard that it was said, ‘An eye for an eye and a tooth for a tooth.’

“But I say to you, do not resist an evildoer. But if anyone strikes you on the right cheek, turn the other also; and if anyone wants to sue you and take your coat, give your cloak as well; and if anyone forces you to go one mile, go also the second mile.

“Give to everyone who begs from you, and do not refuse anyone who wants to borrow from you.”

And then he continues in advising us that we should love even our enemy, and in the Lord's Prayer, Christ links God's forgiveness to our own willingness to forgive.

In Matthew 18, following the conversation with Peter about forgiveness, we get an illustration how outrageous it is, if we want to continue to hold a grudge, while we at the same time believe that we are saved by grace alone.

Peter thought he was on the right track with forgiveness. How often do I have to give my brother or sister another chance? Surely seven times would demonstrate a big heart.

However, Jesus responds by multiplying the number by 11 to 77 times. At that level the actual number is irrelevant though. We can easily recount seven offences with certain people who we have forgiven before, but it would be ridiculous if anybody would try to keep track of forgiveness and then say: “I forgave you 77 times, now it is number 78, now I will take revenge for the last hurt you gave me.” In 1 Corinthians 13:5, Paul says: “[love] keeps no record of wrongs.”

Christ is telling Peter here: when it comes to forgiveness, there is no limit.

But it is interesting how he connects it to The Parable of the Unmerciful Servant that follows.

The reason for us to be willing to forgive others is that God has forgiven us completely.

If we were to compare our debt towards God with what people do to us, it would be like millions of dollars compared to a couple of bugs. In the parable a King forgave his servant 10,000 talents. One talent equals 75 pounds of silver or gold, thus ten thousand talents are 750,000 pounds or 340 metric tons of gold or silver!

That would be today more than $47 billion. After just being forgiven by the king, the very same servant had another servant put into prison for owing him 100 denarii. A hundred denarii are like 100 days of labour, or $5,000 to $15,000 today.

While $5,000 to $15,000 is in everyday life quite a large sum if it is owed, and one would want it back, at the same time the parable shows how ridiculous it is to be unforgiving if you had been forgiven a debt that should have cost you and your family your freedom.

However, it is not about money or economics. This is about learning to love your neighbour.

The Apostle Paul puts it in Romans 14 in the words: “Why do you pass judgment on your brother or sister? Or you, why do you despise your brother or sister? For we will all stand before the judgment seat of God.”

And Christ had said in the Sermon on the Mount: “Do not judge, so that you may not be judged. For with the judgment you make you will be judged, and the measure you give will be the measure you get.”

When it comes to love your neighbour, we cannot hold a grudge or think about revenge any more, because God loves us so much.

It might be an easy idea, but our emotions, when we are hurting, make it so difficult.

Though we also need to know what forgiveness is not.

To forgive does not mean to call wrong behaviour right. It is not to condone or justify injustice, and to forgive does not meant to forget, but it is to give a new chance so that peace can grow.

It might even mean to be more assertive next time you have to deal with that person. And if it is an ongoing abusive relationship, you may forgive, but you also leave that relationship!

To be clear: “Nobody should stay in an abusive relationship. If a perpetrator is unwilling to change even after several conversations, you don’t stay in the relationship.” (Matthew 18:17)

To forgive thus is different from being naive or weak. It can even be tough, especially if the other person is not at all repented or dead already.

Psychologists like Dr Phil tell their clients how important it is to let go of a grudge and forgive, not just for the person who wronged us, but equally for oneself, especially when it comes to what people we loved and trusted might have done to us: family members, parents, spouses, uncles and so on, betrayal that happened, abuse we suffered, or neglect we had to live with.

The good news is that God is willing to forgive whatever we have done, however, he also wants us to learn from him, to be forgiving ourselves. He wants us to begin living as Christians who can overcome the natural, but unhelpful drive to retaliate.

• Karsten Decker is an ordained Lutheran pastor and novelist from Germany who has lived and worked in Bermuda since 2001. At the moment he helps the Centenary Methodist Church at Collectors Hill as pulpit supply.