Mukhtasar Bukhari (Abridged) 99 — Memorizing knowledge is essential

Narrated Abu Huraira (may Allah be pleased with him): I said, "O Messenger of Allah! I hear many hadiths from you but I forget them." So he said, "Spread your cloak." So I spread my cloak, and he scooped with both his hands (and made a symbolic gesture as if pouring something into the cloak), then said, "Wrap it around yourself." So I wrapped it around myself, and after that I never forgot anything.