Musnad Ahmad 1014:12

Surayj ibn al-Nu‘man narrated to us, Hushaym narrated to us, Khalid informed us, Abu Qilabah narrated to us, from Abu Zayd al-Ansari, from the Prophet, peace and blessings of Allah be upon him, the like of that—the like of the hadith of Mansur, from al-Hasan, that a man emancipated six slaves of his. And he said in it: "So he cast lots among them."