Musannaf Ibn Abi Shaybah 30127 — Those who said one who falsely

Yahya bin Sa'id reports that Sa'id bin al-Musayyib said: "The son of a free-born woman of pure lineage and the son of an umm walad insulted each other. Then the son of the free-born woman insulted the son of the umm walad, and for this he was lashed."