Obligatory Charity Tax (Zakat)
Bukhari :: Book 2 :: Volume 24 :: Hadith 576
Narrated Abu Humaid Al-Sa'idi:
Allah's Apostle (p.b.u.h) appointed a man called Ibn Al-Lutbiya, from the tribe of Al-Asd to collect Zakat from Bani Sulaim. When he returned, (after collecting the Zakat) the Prophet checked the account with him.