Narrated Anas: The Prophet said, "When a human being is laid in his grave and his companions return and he even hears their foot steps, two angels come to him and make him sit and ask him: What did you use to say about this man, Muhammad ? He will say: I testify that he is Allah's slave and His Apostle. Then it will be said to him, 'Look at your place in the Hell-Fire. Allah has given you a place in Paradise instead of it.' “The Prophet added, "The dead person will see both his places. But a non-believer or a hypocrite will say to the angels, 'I do not know, but I used to say what the people used to say! It will be said to him, 'Neither did you know nor did you take the guidance (by reciting the Quran).' Then he will be hit with an iron hammer between his two ears, and he will cry and that cry will be heard by whatever approaches him except human beings and Djinns." [Sahih Bukhari. Book 23: Hadith 422]


This notion of life in the grave, questioning and punishing, was borrowed from Jews. Muhammad hadn’t had this idea before Jews of Medina alerted him of this. See the hadith from both Sahih sources:

Narrated Masruq: 'Aisha said that a Jewess came to her and mentioned the punishment in the grave, saying to her, "May Allah protect you from the punishment of the grave." 'Aisha then asked Allah's Apostle about the punishment of the grave. He said, "Yes, (there is) punishment in the grave." 'Aisha added, "After that I never saw Allah's Apostle but seeking refuge with Allah from the punishment in the grave in every prayer he prayed." [Sahih Bukhari. Book: 23, Hadith: 454]