Musnad Abi Ya'la 127 — Sayyiduna Abu Bakr al-Siddiq wrote this

It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) wrote this document for him: "These are the obligations of zakah which Allah Almighty commanded His Messenger (peace and blessings be upon him) with. So whichever of the Muslims is asked for zakah according to its prescribed manner, let him pay it, and whoever is asked for more than that, let him not give it. In fewer than twenty-five camels, on every five camels one goat is due. Then, when the camels reach twenty-five, one 'bint makhad' (a one-year-old female camel) is due on them up to thirty-five; if there is no bint makhad, then an 'ibn labun' (a two-year-old male camel). Then, when the camels reach thirty-six, one 'bint labun' (a two-year-old female camel) is due on them up to forty-five. Then, when they reach forty-six, one 'hiqqah' (a three-year-old female camel ready for mating) is due on them up to sixty. Then, when they reach sixty-one, one 'jadh'ah' (a four-year-old female camel) is due on them up to seventy-five. Then, when they reach seventy-six, two 'bint labun' are due on them up to ninety. Then, when they reach ninety-one, two 'hiqqah' ready for mating are due on them up to one hundred and twenty. Then, when they exceed one hundred and twenty, on every forty one 'bint labun' and on every fifty one 'hiqqah' is due. And in the obligations of zakah, when the ages of the camels differ: whoever owes a 'jadh'ah' in zakah but has no jadh'ah, and has a 'hiqqah' instead, the hiqqah will be accepted from him, and with it he will give two goats, if they are available to him, or twenty dirhams. Whoever owes a 'hiqqah' in zakah but has only a 'jadh'ah', that will be accepted from him, and the zakah collector will give him back twenty dirhams or two goats. Whoever owes a 'hiqqah' but does not have it and has a 'bint labun' instead, that will be accepted from him, and with it he will give two goats, if available, or twenty dirhams. Whoever owes a 'bint labun' but has only a 'hiqqah', that will be accepted from him, and the zakah collector will give him twenty dirhams or two goats. Whoever owes a 'bint labun' but does not have it and has a 'bint makhad' instead, that will be accepted from him, and with it he will give two goats, if available, or twenty dirhams. Whoever owes a 'bint makhad' but has only an 'ibn labun' (a male), that will be accepted from him, and nothing further will be due from him. Whoever has only four camels, no zakah is due on them, unless their owner wishes to give of his own accord. And in the zakah of goats that graze: when they are forty, one goat is due on them up to one hundred and twenty; then, when they are more than that, two goats up to two hundred; then, when they are more than that, three goats up to three hundred; then, when they exceed three hundred by even one, on every hundred one goat. In zakah neither an old animal, nor a defective one, nor the male of the goats (the billy-goat) shall be taken, unless the zakah collector wishes to accept it. For fear of zakah, separate property shall not be combined, nor combined property separated. And whatever belongs to two partners, they shall settle with one another equally (after the zakah is paid). When a man's grazing goats are even one fewer than forty, no zakah is due on them unless their owner wishes. And on silver, zakah is two and a half percent (one fortieth); if the wealth is only one hundred and ninety dirhams, nothing is due on it unless its owner wishes." Abu Khaythamah (may Allah have mercy on him) said: "Al-riqqah" means dirhams.