Musnad Ahmad 1060:97

Aswad ibn Amir narrated to us, Abu Bakr informed us, from al-A’mash, from Abu Dhabyan, who said: Abu Ayyub went on a military expedition with Yazid ibn Mu’awiyah. He said: "When I die, take me into the land of the enemy and bury me beneath your feet where you encounter the enemy." He then said: "I heard the Messenger of Allah, may Allah bless him and grant him peace, say: 'Whoever dies without associating anything with Allah shall enter Paradise.'"