Musnad Ahmad 905:1

Waki’ narrated to us, Aswad bin Shayban narrated to me, from Khalid bin Samir, from Bashir bin Nahik, from Bashir ibn al-Khasasiyah—the bearer of glad tidings of the Messenger of Allah (peace and blessings of Allah be upon him)—that the Messenger of Allah (peace and blessings of Allah be upon him) saw a man walking among the graves wearing two sandals. He said: "O owner of the two Sabtiyyah sandals, cast them off."