Augustine writes to Brother Valentine and his community to defend the Church’s duty to rebuke sinners while insisting that every good movement of the will depends on grace. Law, teaching, exhortation, and correction reveal what is right and expose personal fault, but only the Holy Spirit gives the love and strength to obey; prayer must therefore accompany every rebuke. Rebuke is medicinal, stirring shame and repentance, and even excommunication may serve the offender’s restoration. Predestination does not excuse silence, since no one knows who is elect and God may use human correction as the means of conversion.

The treatise develops this argument through Augustine’s account of original sin, the gift of perseverance, and the distinction between Adam’s freedom to remain good and the stronger grace given through Christ, which creates and sustains the will to persevere. The elect are foreknown, called, justified, and preserved to the end, whereas those who finally fall away were never among the predestined, despite an appearance of temporary faith. Augustine acknowledges the mystery of God’s unequal gifts, including perseverance and the salvation of infants, and rejects human boasting: even the merits rewarded at judgment are themselves gifts of grace. Christians must correct others charitably, pray for their healing, and entrust the hidden outcome to God.