Musannaf Ibn Abi Shayba 17:1366

Waki’ narrated to us, he said: Al-A’mash narrated to us, from Sulayman ibn Maysarah, from Tariq ibn Shihab, from Rafi’ ibn Abi Rafi’ al-Ta’i, who said: I came to Abu Bakr and said: "You commanded me with what you commanded me with, and I entered into what I entered into." He did not cease to offer excuses to me until I excused him.