Musannaf Ibn Abi Shayba 13:1115

Abu Bakr narrated to us, he said: Mu'tamir ibn Sulayman narrated to us, from Zayd ibn Abi al-Mu'alla, a freed slave of Banu Tamim, who said: I witnessed Iyas ibn Mu'awiyah when a dispute was brought before him regarding a slave girl. The man said: "I bought a foolish slave girl from this man." He (Iyas) said: "I do not know of any return (of a purchase) due to foolishness." He said: "Indeed, it is foolishness like madness." He said: So he (Iyas) said to her in Persian: "Do you remember the night you were born?" She said: "Yes." He said: So he said to her: "Which of your two legs is longer?" She said: "One of my legs is this (one)." So he returned her.