Musannaf Ibn Abi Shayba 1:1642

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: "I see your companion teaching you even how to defecate." Salman said: "Yes, he has commanded us not to face the Qibla, and not to clean ourselves with fewer than three stones."