Metamorphoses Book 11: The Cattle of Peleus
While Ceyx told the story, Peleus' herdsmen came in to tell him that a wolf had destroyed half of his herd. Peleus knew that the wolf was punishment for the murder of his brother. Rather than go after the animal, he prayed for forgiveness to Psamathe, the water-nymph mother of his murdered brother. Psamathe forgave him after Thetis did some convincing. To rid the town of the wolf, she turned it to marble. Although she had forgiven Peleus, the Fates would not allow him to find any home in exile.