Musnad Ahmad 33:51

'Abd al-Razzaq narrated to us, Muhammad ibn Muslim informed us, from 'Amr ibn Dinar, from Jabir ibn 'Abd Allah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There is no Zakat on what is less than five awaq (ounces of silver), nor on what is less than five awsuq (loads of dates/grain), nor on what is less than five dhawd (camels)."