Hadith 2319
It is narrated from Abdul Rahman bin Masood that Sayyiduna Sahl bin Abi Hathmah (may Allah be pleased with him) came to us while we were in the market, and he said that the Messenger of Allah (peace and blessings be upon him) said: "When you assess and collect zakat, then forgive (the owner) one third, and if you do not leave him one third, then forgive him one fourth."
Hadith 2320
Sayyiduna Sahl bin Abi Hathmah (may Allah be pleased with him) narrates that the Messenger of Allah (peace be upon him) said: "When you estimate the fruits, then (collect Zakat) according to that, and leave one third. And if you cannot leave one third, then leave one fourth."