The church is the local Christian community.
An unrepentant person (someone refusing to turn from sin) is to be treated as an outsider, like a lawbreaker. Excluding a person from fellowship (sometimes called excommunication) comes from the belief that God’s people must be holy (Acts 5:1–6; Romans 16:17; 1 Corinthians 5:1–13; 2 Corinthians 6:14–18; Galatians 5:7–12; 2 Thessalonians 3:14–15). Sin harms fellowship with both other believers and with God. The goal is not revenge or control, but to restore the sinner to holiness and community (Matthew 18:10–15; Galatians 6:1; James 5:19–20).