Matthew 18:21-35
Back in in Matt 18:15-20, Jesus instructed us in the steps we are to take when someone sins against us. The aim in that passage is not to vindicate ourselves but to gain, or win the brother who has gone astray. That passage does however step through the process as if the person refuses to repent.
Here in this passage however, Jesus teaches us what we are supposed to do when a person does repent. The follower of Christ now has responsibility before God to forgive their brother. Jesus shows us in this parable that it is wickedness before God when we as Christians who have been forgiven such an unpayable debt, turn around and exact justice from those who have sinned against us. Christianity is founded upon God's forgiveness, and we as Christians are supposed to follow God's example in forgiveness.
Therefore, as the elect of God, holy and beloved, put on tender mercies, kindness, humility, meekness, longsuffering; bearing with one another, and forgiving one another, if anyone has a complaint against another; even as Christ forgave you, so you also must do.
- Colossians 3:12-13