Musannaf Ibn Abi Shayba 33:964

Abu Usama narrated to us, he said: Sulayman ibn al-Mughira narrated to us, from Yunus, he said: Al-Hasan said: "The servant remains in goodness as long as he knows what it is that corrupts his deeds for him." Yunus said: "Indeed, among them are those who think they are upon the truth, and among them are those whose desires overcome them."