Sahih Bukhari Volume 007, Book 065, Hadith Number 287I.

Narrated By Abu Huraira : Once while I was in a state of fatigue (because of severe hunger), I met 'Umar bin Al-Khattab, so I asked him to recite a verse from Allah's Book to me. He entered his house and interpreted it to me. (Then I went out and) after walking for a short distance, I fell on my face because of fatigue and severe hunger. Suddenly I saw Allah's Apostle standing by my head. He said, "O Abu Huraira!" I replied, "Labbaik, O Allah's Apostle, and Sadaik!" Then he held me by the hand, and made me get up. Then he came to know what I was suffering from. He took me to his house, and ordered a big bowl of milk for me. I drank thereof and he said, "Drink more, O Abu Hirr!" So I drank again, whereupon he again said, "Drink more." So I drank more till my belly became full and looked like a bowl. Afterwards I met 'Umar and mentioned to him what had happened to me, and said to him, "Somebody, who had more right than you, O 'Umar, took over the case. By Allah, I asked you to recite a Verse to me while I knew it better than you." On that Umar said to me, "By Allah, if I admitted and entertained you, it would have been dearer to me than having nice red camels.