al-Fadl bin Sahl bin Ibrahim الفضل بن سهل بن إبراهيم الأعرج · The Book of Zakah

"I heard the Messenger of Allah say: "No Sadaqah is due on less than five Awsaq of silver, no Sadaqah is due on less than five Dhawd (head) of camels, and no Sadaqah is due on less than five Awsuq of dates."

"The Messenger of Allah said: 'I have exempted you from (having to pay Zakah on) horses and slaves. Pay the Zakah on your wealth, for every two hundred (Dirhams), five."'