Musannaf Ibn Abi Shayba 19:464

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Isma’il bin Abi Khalid, from Mubarak bin ‘Amarah, he said: A woman came to ‘Ali and said: "Woe to her, her husband had intercourse with her slave girl." He said: "If you are truthful, we will stone him, and if you are lying, we will flog you."