Sahih Bukhari, Chapter: Jihaad (Fighting for the cause of Allah)

Um Haram told me that the Prophet one day took a midday nap in her house. Then he woke up smiling. Um Haram asked, "O Allah's Apostle (SAW) (SAW)! What makes you smile?" He replied "I was astonished to see (in my dream) some people amongst my followers on a sea-voyage looking like kings on the thrones." She said, "O Allah's Apostle (SAW) (SAW)! Invoke Allah to make me one of them." He replied, "You are amongst them." He slept again and then woke up smiling and said the same as before twice or thrice. And she said, "O Allah's Apostle (SAW) (SAW)! Invoke Allah to make me one of them." And he said, "You are amongst the first batch." 'Ubada bin As-Samit married her (i.e. Um Haram) and then he took her for Jihad. When she returned, an animal was presented to her to ride, but she fell down and her neck was broken. (And she died).