Sahih al-Bukhari, Volume 2, Book 23, Hadith 452 (USC-MSA)

Narrated Ibn `Umar: The Prophet looked at the people of the well (the well in which the bodies of the pagans killed in the Battle of Badr were thrown) and said, "Have you found true what your Lord promised you?" Somebody said to him, "You are addressing dead people." He replied, "You do not hear better than they but they cannot reply."

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ، حَدَّثَنِي أَبِي، عَنْ صَالِحٍ، حَدَّثَنِي نَافِعٌ، أَنَّ ابْنَ عُمَرَ ـ رضى الله عنهما ـ أَخْبَرَهُ قَالَ اطَّلَعَ النَّبِيُّ صلى الله عليه وسلم عَلَى أَهْلِ الْقَلِيبِ فَقَالَ ‏"‏ وَجَدْتُمْ مَا وَعَدَ رَبُّكُمْ حَقًّا ‏"‏‏.‏ فَقِيلَ لَهُ تَدْعُو أَمْوَاتًا فَقَالَ ‏"‏ مَا أَنْتُمْ بِأَسْمَعَ مِنْهُمْ وَلَكِنْ لاَ يُجِيبُونَ ‏"‏‏.‏

sunnah.com