Maliks Muwatta Book 17, Hadith Number 13.
Section : The Zakat on the Property of Orphans and Trading on their Behalf.
Yahya related to me from Malik from Abd ar-Rahman ibn al-Qasim that his father said, ”A’isha used to look after me and one of my brothers – we were orphans – in her house, and she would take the zakat from our property.”