Musannaf Ibn Abi Shayba 19:898

Abu Bakr narrated to us, he said: Abu ‘Isam narrated to us, from al-Awza’i, from al-Zuhri, regarding a man who says to a man from the Arabs, "You are a *mawla* (freed slave/client)." He said: The prescribed punishment (*hadd*) is to be administered to him.