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