Musannaf Ibn Abi Shayba 33:621

Abu Usama narrated to us, he said: Sufyan al-Thawri narrated to us, from his father, from Bakr ibn Ma'iz, who said: Al-Rabi' ibn Khuthaym said: "O Bakr, restrain your tongue except for what is for you and not against you, for I have become suspicious of people regarding my religion. Obey Allah in what you do, and as for what has been kept away from you, entrust it to its Knower. For I am more fearful for you regarding intentional acts than I am for you regarding mistakes. Your good today is not [absolute] good, but it is better than a later time that is worse than it. You do not follow all of the good as it should be followed, nor do you flee from evil as it should be fled from. You have not grasped everything that Allah revealed to Muhammad, nor do you understand everything that you read. The secrets that are hidden from people are for Allah in the valleys; seek their remedy." Then he would say to himself: "And what is their remedy? It is that you repent, then do not return [to the sin]."