Musannaf Ibn Abi Shayba 35:262

Waki’ narrated to us, from al-A’mash, from Ibrahim, from ‘Abd al-Rahman ibn Yazid, from Salman: Some of the polytheists said to him, while they were mocking, "Your companion teaches you everything, even how to defecate." Salman said, "Yes, he has commanded us not to face the qibla, not to clean ourselves with our right hands, and not to suffice with fewer than three stones, which contain neither dung nor bone."