Musnad Abu Ya'la al-Mawsili 152:287

Abu Khaythama narrated to us, Mu'awiyah ibn 'Amr narrated to us, Za'idah narrated to us, 'Asim narrated to us, from Zirr, from 'Abdullah, who said: A black slave caught up with the Prophet, may Allah bless him and grant him peace, and then he died. The Prophet, may Allah bless him and grant him peace, was informed about him, so he said: "Look, did he leave anything behind?" They said: "He left behind two dinars." He said: "Two brandings."