Imām Al-Shāfi'ī said:

Whenever any people of desires (heretics) came to Mālik he would say to them, "As for me, I am upon clarity as regards my religion. As for you, you are a doubter, go and argue with another doubter like yourself."

Al-Dhahbī in Siyar A'lām Al-Nubalā' under the biography of Imām Mālik.