Sahih Bukhari
Obligatory Charity Tax (Zakat)
Volume: 002 / Book Number: 024 / Hadith Number: 495
Narrated Abu Musa:
Thy Prophet (p.b.u.h) said, "A time will come upon the people when a person will wander about with gold as Zakat and will not find anybody to accept it, and one man will be seen followed by forty women to be their guardian because of scarcity of men and great number of women. "