Obligatory Charity Tax (Zakat)

Bukhari :: Book 2 :: Volume 24 :: Hadith 511

Narrated Ibn Abbas:

The Prophet went out for the 'Id prayer on the 'Id day and offered a two Rakat prayer; and he neither offered a prayer before it or after it. Then he went towards the women along with Bilal. He preached them and ordered them to give in charity. And some (amongst the women) started giving their fore-arm bangles and ear-rings.