Sahih Bukhari
Obligatory Charity Tax (Zakat)
Volume: 002 / Book Number: 024 / Hadith Number: 510
Narrated 'Uqba bin Al-Harith:
Once the Prophet offered the 'Asr prayer and then hurriedly went to his house and returned immediately. I (or somebody else) asked him (as to what was the matter) and he said, "I left at home a piece of gold which was from the charity and I disliked to let it remain a night in my house, so I got it distributed . "