Sahih Bukhari Volume 9, Book 87, Hadith Number 148.

Narrated By Abu Huraira : Allah’s Apostle said, “While I was sleeping, I saw myself standing at a well over which there was a bucket. I pulled out from it as many buckets of water as Allah wished, and then Ibn Abi Quhafa (Abu Bakr) took the bucket from me and pulled out one or two full buckets, and there was weakness in his pull… may Allah forgive him. Then the bucket turned into a very large one and ‘Umar bin Al-Khattab took it. I have never seen any strong man among the people, drawing water with such strength as ‘Umar did, till the people (drank to their satisfaction and) watered their camels to their fill; whereupon the camels sat beside the water.”