So far in this sermon in Matthew 18, Jesus employed five accounts to teach Christian disciples how to love: 1) those in the world by limiting our freedom (17:24-26); 2) fellow-Christians with humble service (18:1-5); 3) weaker brethren through self-denial (18:6-9); 4) wandering Christians with relentless concern and outreach (18:10-14); and 5) sinning Christians by confrontation, and if necessary discipline or excommunication (18:15-20). What may be striking to us as we have been studying Matthew 18 is the seriousness with which sin is dealt with. No measure is to be left untaken in our effort to put sin to death in ourselves and in our brothers and sisters in the church. This shows us the importance of our “mission field” within our own local church. Our integrity as a church depends on our placing an equal emphasis on outreach to the world and “inreach” within the church. When we join ourselves to a local body of Christ, we become “our brother’s keeper,” as we strive together to make it to our final destination. So mortification of sin is a group-project, where we help each other to identify and root out sin.
But Jesus does not want to leave us with excommunication as the final word of this sermon – His last word is, forgiveness. In the course of living life together, individuals in the church will inevitably sin against each another. Part of our growth as Christians involves bearing with one another’s different sinful tendencies, and forgiving one another is paramount. In Matthew 18, verses 21-35, Jesus concludes this sermon on how to love one another with a strong exhortation of the absolute necessity for the Christian to forgive. The illustration of the unmerciful servant in our text reveals that forgiveness is so essential to our faith, that if we do not extend it to others, then we will find ourselves under God’s judgment. This parable stands as a warning to those in the church to examine themselves for the damning sin of unforgiveness. This text, along with parallel teaching from the apostle Paul in Ephesians 4:32 and Colossians 3:13, reveals that extending forgiveness to others is a behavior that comes as a result of the heart-change that we receive when we are forgiven our massive sin debt by Christ. It is with an overwhelming sense of gratitude then, that the Christian’s life becomes defined by charitable forgiveness.