Musnad Ahmad 32:1137

Yazid narrated to us, Humaid informed us, from Anas, that the Prophet, may Allah bless him and grant him peace, passed by some date palms belonging to Banu al-Najjar, and he heard a sound. He said: "What is this?" They said: "The grave of a man who was buried during the Jahiliyyah (pre-Islamic period)." The Messenger of Allah, may Allah bless him and grant him peace, said: "Were it not that you would not bury one another, I would have supplicated to Allah to let you hear the punishment of the grave."