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