Jerome writes to Rusticus at Artemia’s request, grieving that her former husband has not followed her to the Holy Land after their broken vow of continence. Biblical examples from Lot, Samuel, Paul, David, Ahab, and Nineveh show that the holy grieve over sin, seek the conversion of others, and trust in God’s desire to restore the wicked rather than destroy them. Sincere sorrow, confession, and a contrite heart obtain mercy even after grave wrongdoing, whereas concealment and stubbornness leave the sinner without peace. Jerome therefore presses Rusticus to abandon worldly attachments, honour his promise, and join Artemia in penance. Her steadfastness and prayers stand as both rebuke and intercession for him. The letter presents divine mercy as actively seeking the lost and uses Rusticus’s situation to urge immediate repentance before spiritual indifference hardens into ruin.