Hadith 5:913
Waki’ narrated to us, from Sharik, from Khusayf (Husayn), from Mujahid, who said: The family of Muhammad, may Allah bless him and grant him peace, were not permitted to receive charity, so the fifth of the fifth was made for them.
حدثنا وكيع عن شريك عن خصيف ( ( ( حصين ) ) ) عن مجاهد قال كان آل محمد صلى الله عليه وسلم لا تحل لهم الصدقة فجعل لهم خمس الخمس