Narrated Jabir:
Allah’s Apostle came to visit me while I was sick and unconscious. He performed ablution and sprinkled the remaining water on me and I became conscious and said, “O Allah’s Apostle! To whom will my inheritance go as I have neither ascendants nor descendants?” Then the Divine verses regarding Fara’id (inheritance) were revealed.
Sahih Bukhari, Volume 1, Book4, Number 193