Sahih Muslim Book 004, Hadith Number 1214.
Chapter : Dhikr after the prayer.
'Aisha reported: There came to me two old women from the old Jewesses of Medina and said: The people of the grave are tormented in their graves. I contradicted them and I did not deem it proper to testify them. They went away and the Messenger of Allah (may peace be upon him) came to me and I said to him: Messenger of Allah I there came to me two old women from the old Jewesses of Medina and asserted that the people of the graves would be tormented therein. He (the Prophet) said: They told the truth; they would be tormented (so much) that the animals would listen to it. She ('Aisha) said: Never did I see him (the Holy Prophet) afterwards but seeking refuge from the torment of the grave in prayer.