'Aayeshah Radiyallahu 'Anha says that Rasulullah Sallallhu 'Alayhi Wasallam said:
"We have no heirs. What we (the ambiyaa) leave is sadaqah" (RU)
English reference (RU): Book 54, Hadith 385 (RU)
Arabic reference (RU): Book 55, Hadith 402 (RU)