Musnad Ahmad 30:720

He said: And Ya‘qub narrated it to us, my father narrated to us, from Ibn Ishaq, who said: And al-‘Ala’ ibn ‘Abd al-Rahman ibn Ya‘qub, the freed slave of al-Huraqah, narrated to me, from Abu al-Sa’ib, the freed slave of ‘Abd Allah ibn Zuhrah al-Taymi, from Abu Hurayrah, and he mentioned the hadith.