Musnad Ahmad 1060:63

Ibn Numayr narrated to us, from al-A‘mash, who said: I heard Abu Dhabyan and Ya‘la. Al-A‘mash narrated to us, from Abu Dhabyan, who said: Abu Ayyub went on a military expedition to the Byzantines and became ill. When he was near death, he said: "When I die, carry me, and when you line up against the enemy, bury me beneath your feet. And I will tell you a hadith I heard from the Messenger of Allah (peace and blessings of Allah be upon him); were it not for my current state, I would not have told it to you. I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: 'Whoever dies without associating anything with Allah shall enter Paradise.'"