“I complained to Waki‘ of my poor memory, and he guided me to leave off sins, and told me that knowledge is light, and the light of Allah is not given to one who disobeys.”

Al-Shafi‘i addressed these lines to his teacher Waki‘ ibn al-Jarrah, the great hadith scholar of Kufa, and they are among the best known in the Diwan attributed to him. The answer he records is not study advice: the trouble was not method but sin, since knowledge is a light and light does not settle on a heart that keeps disobeying. “Knowledge is light” has since become a proverb on its own.