Sahih al-Bukhari 1398
Obligatory Charity Tax (Zakat)
The obligation of Zakat
Narrated Ibn `Abbas: A delegation of the tribe of `Abdul Qais came to the Prophet (ﷺ) and said, "O Allah's Messenger (ﷺ) ! We are from the tribe of Rabi`a, and the infidels of the tribe of Mudar stands between us and you; so we cannot come to you except during the Sacred Months. Please order us to do something (religious deeds) which we may carry out and also invite to it our people whom we have left behind." The Prophet (ﷺ) said, "I order you to do four things and forbid you four others: (I order you) to have faith in Allah, and confess that none has the right to be worshipped but Allah, (and the Prophet (ﷺ) gestured with his hand like this (i.e. one knot) and to offer prayers perfectly and to pay the Zakat, and to pay onefifth of the booty in Allah's Cause. And I forbid you to use Dubba', Hantam, Naqir and Muzaffat (all these are the names of utensils used for preparing alcoholic drinks)."