Obligatory Charity Tax (Zakat)

Bukhari :: Book 2 :: Volume 24 :: Hadith 503

Narrated Ma'n bin Yazid:

My grandfather, my father and I gave the pledge of allegiance to Allah's Apostle. The Prophet got me engaged and then got me married. One day I went to the Prophet with a complaint. My father Yazid had taken some gold coins for charity and kept them with a man in the mosque (to give them to the poor) But I went and took them and brought them to him (my father). My father said, "By Allah! I did not intend to give them to you. " I took (the case) to Allah's Apostle . On that Allah's Apostle said, "O Yazid! You will be rewarded for what you intended. O Man! Whatever you have taken is yours."