Sahih Bukhari Volume 004, Book 052, Hadith Number 047.

Narated By Anas bin Malik : Allah's Apostle used to visit Um Haran bint Milhan, who would offer him reals. Um-Haram was the wife of Ubada bin As-Samit. Allah's Apostle, once visited her and she provided him with food and started looking for lice in his head. Then Allah's Apostle slept, and afterwards woke up smiling. Um Haran asked, "What causes you to smile, O Allah's Apostle?" He said. "Some of my followers who (in a dream) were presented before me as fighters in Allah's Cause (on board a ship) amidst this sea cause me to smile; they were as kings on the thrones (or like kings on the thrones)." (Ishaq, a sub-narrator is not sure as to which expression the Prophet used.) Um-Haram said, "O Allah's Apostle! Invoke Allah that he makes me one of them. Allah's Apostle invoked Allah for her and slept again and woke up smiling. Once again Um Haram asked, "What makes you smile, O Allah's Apostle?" He replied, "Some of my followers were presented to me as fighters in Allah's Cause," repeating the same dream. Um-Haram said, "O Allah's Apostle! Invoke Allah that He makes me one of them." He said, "You are amongst the first ones." It happened that she sailed on the sea during the Caliphate of Mu'awlya bin Abi Sufyan, and after she disembarked, she fell down from her riding animal and died.