Musannaf Ibn Abi Shayba 21:27

Abu Mu'awiyah narrated to us, from al-A'mash, from Abu Sufyan, from Jabir, from Umm Mubashir, who said: The Prophet, may Allah bless him and grant him peace, entered upon me while I was in one of the gardens of the Banu al-Najjar, in which there were graves of some of them who had died during the Jahiliyyah. She said: He went out, and I heard him saying: "Seek refuge in Allah from the punishment of the grave."