The Prophet ﷺ said, "When a faithful believer is made to sit in his grave, then (the angels) come to him and he testifies that none has the right to be worshipped but Allah and Muhammad is Allah's Apostle. And that corresponds to Allah's statement: Allah will keep firm those who believe with the word that stands firm . . . (14.27). Narrated Shu'ba: Same as above and added, "Allah will keep firm those who believe . . . (14.27) was revealed concerning the punishment of the grave."  

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا أُقْعِدَ الْمُؤْمِنُ فِي قَبْرِهِ أُتِيَ ثُمَّ شَهِدَ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ فَذَلِكَ قَوْلُهُ {يُثَبِّتُ اللَّهُ الَّذِينَ آمَنُوا بِالْقَوْلِ الثَّابِتِ} حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ حَدَّثَنَا غُنْدَرٌ حَدَّثَنَا شُعْبَةُ بِهَذَا وَزَادَ {يُثَبِّتُ اللَّهُ الَّذِينَ آمَنُوا} نَزَلَتْ فِي عَذَابِ الْقَبْرِ  

The Prophet ﷺ 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."  

أَخْبَرَهُ قَالَ اطَّلَعَ النَّبِيُّ ﷺ عَلَى أَهْلِ الْقَلِيبِ فَقَالَ وَجَدْتُمْ مَا وَعَدَ رَبُّكُمْ حَقًّا فَقِيلَ لَهُ تَدْعُو أَمْوَاتًا فَقَالَ مَا أَنْتُمْ بِأَسْمَعَ مِنْهُمْ وَلَكِنْ لاَ يُجِيبُونَ  

The Prophet ﷺ said, "They now realize that what I used to tell them was the truth. "And Allah said, 'Verily! You cannot make the dead to hear (i.e. benefit them, and similarly the disbelievers) nor can you make the deaf hear. (27.80).  

قَالَ النَّبِيُّ ﷺ إِنَّهُمْ لَيَعْلَمُونَ الآنَ أَنَّ مَا كُنْتُ أَقُولُ حَقٌّ وَقَدْ قَالَ اللَّهُ تَعَالَى {إِنَّكَ لاَ تُسْمِعُ الْمَوْتَى}  

ʿAisha 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." ʿAisha then asked Messenger of Allah ﷺ about the punishment of the grave. He said, "Yes, (there is) punishment in the grave." ʿAisha added, "After that I never saw Messenger of Allah ﷺ but seeking refuge with Allah from the punishment in the grave in every prayer he prayed."  

أَنَّ يَهُودِيَّةً دَخَلَتْ عَلَيْهَا فَذَكَرَتْ عَذَابَ الْقَبْرِ فَقَالَتْ لَهَا أَعَاذَكِ اللَّهُ مِنْ عَذَابِ الْقَبْرِ فَسَأَلَتْ عَائِشَةُ رَسُولَ اللَّهِ ﷺ عَنْ عَذَابِ الْقَبْرِ فَقَالَ نَعَمْ عَذَابُ الْقَبْرِ قَالَتْ عَائِشَةُ ؓ فَمَا رَأَيْتُ رَسُولَ اللَّهِ ﷺ بَعْدُ صَلَّى صَلاَةً إِلاَّ تَعَوَّذَ مِنْ عَذَابِ الْقَبْرِ زَادَ غُنْدَرٌ عَذَابُ الْقَبْرِ حَقٌّ  

Messenger of Allah ﷺ once stood up delivering a sermon and mentioned the trial which people will face in the grave. When he mentioned that, the Muslims started shouting loudly.  

أَنَّهُ سَمِعَ أَسْمَاءَ بِنْتَ أَبِي بَكْرٍ ؓ تَقُولُ قَامَ رَسُولُ اللَّهِ ﷺ خَطِيبًا فَذَكَرَ فِتْنَةَ الْقَبْرِ الَّتِي يَفْتَتِنُ فِيهَا الْمَرْءُ فَلَمَّا ذَكَرَ ذَلِكَ ضَجَّ الْمُسْلِمُونَ ضَجَّةً  

Messenger of Allah ﷺ said, "When (Allah's) slave is put in his grave and his companions return and he even hears their footsteps, two angels come to him and make him sit and ask, 'What did you use to say about this man (i.e. Muhammad)?' The faithful Believer will say, 'I testify that he is Allah's slave and His Apostle.' Then they will say to him, 'Look at your place in the Hell Fire; Allah has given you a place in Paradise instead of it.' So he will see both his places." (Qatada said, "We were informed that his grave would be made spacious." Then Qatada went back to the narration of Anas who said;) Whereas a hypocrite or a non-believer will be asked, "What did you use to say about this man." He will reply, "I do not know; but I used to say what the people used to say." So they will say to him, "Neither did you know nor did you take the guidance (by reciting the Qur'an)." Then he will be hit with iron hammers once, that he will send such a cry as everything near to him will hear, except Jinns and human beings. (See Hadith No. 422).  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ إِنَّ الْعَبْدَ إِذَا وُضِعَ فِي قَبْرِهِ وَتَوَلَّى عَنْهُ أَصْحَابُهُ وَإِنَّهُ لَيَسْمَعُ قَرْعَ نِعَالِهِمْ أَتَاهُ مَلَكَانِ فَيُقْعِدَانِهِ فَيَقُولاَنِ مَا كُنْتَ تَقُولُ فِي الرَّجُلِ لِمُحَمَّدٍ ﷺ فَأَمَّا الْمُؤْمِنُ فَيَقُولُ أَشْهَدُ أَنَّهُ عَبْدُ اللَّهِ وَرَسُولُهُ فَيُقَالُ لَهُ انْظُرْ إِلَى مَقْعَدِكَ مِنَ النَّارِ قَدْ أَبْدَلَكَ اللَّهُ بِهِ مَقْعَدًا مِنَ الْجَنَّةِ فَيَرَاهُمَا جَمِيعًا قَالَ قَتَادَةُ وَذُكِرَ لَنَا أَنَّهُ يُفْسَحُ فِي قَبْرِهِ ثُمَّ رَجَعَ إِلَى حَدِيثِ أَنَسٍ قَالَ وَأَمَّا الْمُنَافِقُ وَالْكَافِرُ فَيُقَالُ لَهُ مَا كُنْتَ تَقُولُ فِي هَذَا الرَّجُلِ فَيَقُولُ لاَ أَدْرِي كُنْتُ أَقُولُ مَا يَقُولُ النَّاسُ فَيُقَالُ لاَ دَرَيْتَ وَلاَ تَلَيْتَ وَيُضْرَبُ بِمَطَارِقَ مِنْ حَدِيدٍ ضَرْبَةً فَيَصِيحُ صَيْحَةً يَسْمَعُهَا مَنْ يَلِيهِ غَيْرَ الثَّقَلَيْنِ