There are two aspects in connection with forgiving a sinning brother that can be distinguished in Scripture. First, we are always responsible to forgive in the sense of never holding grudges and bitterness. Without this, we would be unable to reach out in love to bring about healing or to help a person grow through a life-dominating problem and help them get right with the Lord. But on the hand, we are not able to forgive in the sense of ignoring persistence in sin by a stubborn and rebellious believer. We have the responsibility to rebuke (though in love) and to refuse intimate fellowship if the sinning believer is unwilling to confess and deal with the sin. It’s a matter of ‘tough love,’ as it has been popularly phrased. Failure to confess or repent of sin is an indication of rebellion and will lead to serious consequences to self, to others, and to the church.
The goal is never revenge or to hurt, but restoration and healing: to get the sinning party to get his or her life right with the Lord so God is free to work in their life for their own growth and change. The goal is spiritual restoration (see Gal. 6:1f).