The Catholic obligation to practice fraternal correction, guiding souls away from sin toward repentance and holiness
To admonish the sinner is to practice fraternal correction—warning those in sin to repent and return to God. Christ commands: "If your brother sins, rebuke him" (Luke 17:3). The CCC teaches: "Fraternal correction is an obligation of charity" (CCC 1829). This work flows from love: love for God whose honor is offended by sin, and love for neighbor whose soul is in peril.
Leviticus 19:17: "Reason with your neighbor, lest you bear sin." Ezekiel 3:18-21: Watchman accountable for warning the wicked. Matthew 18:15-17: Christ's procedure for fraternal correction. Galatians 6:1: "Restore him in a spirit of gentleness." James 5:19-20: "Bring back a sinner from his error will save his soul from death."
Early Church: Public penance for grave sins. St. Paul admonished the Corinthians (1 Cor 5). St. Ambrose (AD 390) barred Emperor Theodosius from Eucharist until he repented of massacre. Medieval: Confession formalized; confessors admonished penitents. Trent (1551): Reaffirmed necessity of confession and pastoral correction.
To admonish the sinner is a spiritual work of mercy commanded by Christ and practiced throughout Church history. It requires courage, prudence, and genuine charity. The goal is always conversion, not condemnation. Catholics fulfill this by encouraging confession, praying for sinners, and gently correcting when appropriate. St. Thomas Aquinas teaches that fraternal correction is an obligation "when there is hope of amendment" (ST II-II, Q. 33). When done rightly, it saves souls and glorifies God.