The Lord Jesus Christ came into the world not only to reconcile us to God, but to reconcile us to each other as well. In Matthew 6 and in other places (Matthew 18:21f; Mark 11:25; Luke 17:4; Colossians 3:3; Ephesians 4:32) we see the great emphasis the Lord put upon our need to pardon those who have sinned against us. We should not make light of a matter which the Lord has placed such stress and high importance.
Matthew 6 does not teach that our eternal destiny is based on us forgiving other people; it does teach that our rapport with God will be ruined in innumerable ways if we fail to pardon those who have offended us.
Throughout history God has pardoned sin by His grace based on Christ’s work on the cross alone, not on man’s actions. Our right standing before Him is established on one thing only: the finished work of Christ (John 19:30, compare with 1 John 2:2; 1 John 4:10; Revelation 5:9; and others too numerous to mention). We are released from our sins by His blood (Revelation 1:5). He has reconciled us in His earthly body through His death (Colossians 1:22). Jesus bore our sins in His own Body on the cross so that by His wounds we are healed (1 Peter 2:24). We are made holy through the offering up of Jesus’ Body as a sacrifice once for all (Hebrews 10:10). Christ appeared once for all to put away sin by the sacrifice of Himself (Hebrews 9:26). God sent His Son to remove the wrath that we ourselves deserved (1 John 4:10). The penalty of sin that is rightly ours is absolved by grace through faith, not by any righteous deeds of our own (Ephesians 2:8-9). No one will be able to stand before God demanding that their sins be forgotten simply because they have forgiven others. Only when we are born again, given a new life through God’s Spirit, by faith in Jesus Christ are we forgiven of our sins. Therefore, Jesus does not have in mind God’s initial act of forgiveness (reconciliation) that we had experienced when we first believed the Gospel.
In Matthew 6 Jesus is teaching disciples how to pray and in doing so outlines how we are restored into intimacy with God whenever we have displeased Him. In fact, Jesus instructs us to build into our prayers a request that God forgives us in the same way that we have forgiven others who have harmed us (Matthew 6:12).
If there are those we have not forgiven when we ourselves pray for forgiveness, then practically speaking we are asking God not to restore a right relationship with us after we sin. To emphasize the importance of restoring broken relationships with our brothers and sisters, He states that by asking for God’s forgiveness for one’s own sins all the while withholding forgiveness from someone else is not only bizarre but hypocritical. One cannot possibly walk with God if he refuses to forgive others.
To be sure, an unforgiving spirit is an extremely serious sin and should be confessed to God. If we have unforgiveness in our hearts against someone else then we are acting in a way that is not pleasing God making our prayers difficult and a proper living relationship with Him utterly impossible. God will not hear our prayers unless we also show ourselves ready to grant forgiveness.
If we are harder than iron in this regard, Christ’s exhortation ought to soften us! – John Calvin