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