And Muhammad ibn al-Muthanna and Ibn Bashshar narrated to us — and the wording is that of Ibn al-Muthanna — they said: Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Firas, who said: I heard Dhakwan narrating from Zadhan, that Ibn 'Umar called for a slave of his, and he saw a mark on his back. He said to him, "Did I hurt you?" He said, "No." He said, "Then you are free." He said: Then he took something from the ground and said, "I have no reward in it equal to the weight of this. Indeed, I heard the Messenger of Allah, peace and blessings be upon him, say: 'Whoever strikes his slave a blow for which he has no justification, or slaps him, then his expiation is to free him.'"