Mujahid narrates from Abdullah bin Umar (may Allah be pleased with them both): The Prophet Muhammad (peace be upon him) granted some land to his servant Abu Rafi’ (may Allah be pleased with him). He was unable to take care of it, and he passed away. Umar bin Khattab (may Allah be pleased with him) sold that land for one hundred and eighty thousand dinars. He appointed Ali bin Abi Talib (may Allah be pleased with him) as the custodian of that amount. Ali (may Allah be pleased with him) used to pay its zakat every year, until the children of Abu Rafi’ (may Allah be pleased with him) grew up, and then they found that wealth to be little. Ali (may Allah be pleased with him) asked:“Have you calculated the zakat for it?”They replied:“Yes!”Ali (may Allah be pleased with him) said:“Calculate its zakat.”When they calculated it, they found it to be complete.