Obligatory Charity Tax (Zakat)

Bukhari :: Book 2 :: Volume 24 :: Hadith 491

Narrated Abu Huraira

Allah's Apostle said, "If one give in charity what equals one date-fruit fro the honestly-earned money and Allah accepts only the honestly earned money --Allah takes it in His right (hand) ar then enlarges its reward for that person (who has given it), as anyone of you brings up his baby horse, so much s that it becomes as big as a mountain