What did the Prophet Muhammad (saw) ask Abu Huraira to do when Abu Huraira said he heard many narrations from the Prophet (saw) but forgot them?
 Narrated Abu Huraira:                     I said, "O Allah's Apostle! I hear many narrations from you but I forget them." He said, "Spread your covering sheet." I spread my sheet and he moved both his hands as if scooping something and emptied them in the sheet and said, "Wrap it." I wrapped it round my body, and since then I have never forgotten.