Sayyiduna Ali (may Allah be pleased with him) narrates from the Noble Prophet (peace and blessings be upon him) that he said: "I have exempted you from zakat on horses and slaves, therefore pay one dirham of zakat for every forty dirhams from your wealth." Sayyiduna Ali (may Allah be pleased with him) says: "For every forty dinars, one dinar, and for every twenty dinars, there is zakat."