Musannaf Ibn Abi Shayba 28:110

Abu Mu'awiyah narrated to us, from al-A'mash, from Ibrahim, from Masruq, who said: When the Messenger of Allah (may Allah bless him and grant him peace) sent Mu'adh to Yemen, he commanded him to take from every adult (halim) one dinar or its equivalent in Mu'afiri (garments).