Abu Dawud Book 12, Hadith Number 2880.
Chapter : On the shares of those who leave no descendants or asvendants as heirs.
Narated By Jabir : I fell ill, and the Prophet (PBUH) and Abu Bakr came to me on foot to visit me. As I was unconscious, I could not speak to him. He performed ablution and sprinkled water on me; so I became conscious. I said: Apostle of Allah, how should I do in my property, as I have sisters? Thereafter the verse about inheritance was revealed: “They ask thee for legal decision. Say: Allah directs (thus) about those who leave no descendants or ascendants as heirs.”