Musannaf Ibn Abi Shayba 33:963

Abu Usama narrated to us, from Sufyan, from Imran al-Qasir, who said: I asked al-Hasan about something, and I said, "The jurists (fuqaha) say such and such." He said, "And have you seen a jurist with your own eyes? The jurist is only the one who is ascetic regarding the world, insightful regarding his religion, and constant in the worship of his Lord."