Khbyb bin 'Abdur Rahman خبيب بن عبد الرحمن بن خبيب · The Book on Zakat

"Sahl bin Abi Hathmah came to a gathering of ours, and he narrated that the Messenger of Allah would say: "When you make an assessment, then take it and leave a third, if you do not leave a third, then leave a quarter."