And if he refuses to hear them, tell it to the church. But if he refuses even to hear the church, let him be to you like a heathen and a tax collector. (Matthew 18:17, NKJV)
In Matthew 18:15-17, the Lord teaches a deliberate approach to resolving sinful conflict between His disciples. Each step is designed to seek and save the lost (Matthew 18:10-14). At this point, previous attempts have failed to bring the sinning brother to repentance concerning his sin against a brother. Now, it is time to inform the church of the Christian’s lack of repentance, so the church can get involved in trying to rescue the sinner (James 5:19-20). Each member of the church is to reach out to the erring Christian, attempting to bring him or her back to the Lord’s salvation. By taking a united action of trying to save the sinner, the church is being careful not to put a stumbling block before Christ’s little one (remember the broader context of this passage, Matthew 18:6-14). Now is the time for each Christian to work to bring the sinner to repentance. That is why a private sin now must be made public to the church. A soul is in danger!