Sahih Muslim Book 40, Hadith Number 6869.
Anas b. Malik reported that Allah’s Messenger (may peace be upon him) let the dead bodies of the unbelievers who fought in Badr (lie unburied) for three days. He then came to them and sat by their side and called them and said: O Abu Jahl b. Hisham, O Umayya b. Khalaf, O Utba b. Rab’ila, O Shaiba b. Rabi’a, have you not found what your Lord had promised with you to be correct? As for me, I have found the promises of my Lord to be (perfectly) correct. Umar listened to the words of Allah’s Apostle (may peace be upon him) and said: Allah’s Messenger, how do they listen and respond to you? They are dead and their bodies have decayed. Thereupon he (the Holy Prophet) said: By Him in Whose Hand is my life, what I am saying to them, even you cannot hear more distinctly than they, but they lack the power to reply. Then he commanded that they should be buried in the well of Badr.