Musnad Ahmad 32:2120

'Affan narrated to us, Hammad narrated to us, from Thabit, from Anas, that the Messenger of Allah (peace and blessings of Allah be upon him) left the slain of Badr for three days until they decomposed. Then he came to them and stood over them and said: "O Umayyah ibn Khalaf, O Abu Jahl ibn Hisham, O 'Utbah ibn Rabi'ah, O Shaybah ibn Rabi'ah, have you found what your Lord promised you to be true? For I have found what my Lord promised me to be true." 'Umar heard his voice and said: "O Messenger of Allah, do you call out to them after three days, and can they hear? Allah the Almighty says: 'Indeed, you cannot make the dead hear' [An-Naml: 80]?" He said: "By the One in Whose hand is my soul, you are not more hearing than they are, but they are unable to answer."