Musannaf Ibn Abi Shayba 33:574

Muhammad ibn Fudayl narrated to us, from al-A'mash, from Sulaym al-'Amiri, who said: I heard Hudhayfah saying: "It is sufficient for a person in terms of knowledge that he fears Allah, and it is sufficient for him in terms of lying that he says 'I seek forgiveness from Allah' and then returns [to the sin]."