Abyad went to the Messenger of Allah (ﷺ) and asked him for assigning him (the mines of) salt as fief. (The narrator Ibn al-Mutawakkil said: which was in Ma’arib.) So he assigned it to him as a fief. When he returned, a man in the meeting asked: Do you know what you have assigned him as a fief? You have assigned him the perennial spring water. So he took it back from him. He asked him about protecting land which had arak trees growing in it. He replied: He could have such as was beyond the region where the hoofs (of camels) went. The narrator Ibn al-Mutwakkil said: “that is the camel hoofs.”
Then al-Hasan forgot this tradition, and he used to say: A free man is not to be killed for a slave.