Short answer
Two angels, known as Munkar and Nakir, ask every person three questions: Who is your Lord? What is your religion? Who is this man who was sent among you? The believer answers: my Lord is Allah, my religion is Islam, and he is the Messenger of Allah ﷺ. Sunni creed affirms the questioning and the reward or punishment of the grave.
The questioning by Munkar and Nakir, the return of the soul to the body in the grave, and the punishment of the grave for disbelievers and some sinful Muslims are true and part of Sunni creed. Imam Abu Hanifa states this in al-Fiqh al-Akbar.
The four schools agree on this.
Explanation
The long hadith of al-Bara ibn Azib in Abu Dawud describes the scene. Two angels come to the dead person, sit him up and ask, "Who is your Lord?" He says, "My Lord is Allah." They ask, "What is your religion?" He says, "My religion is Islam." They ask about the man sent among them, and he says, "He is the Messenger of Allah." A caller from heaven then announces that he has spoken the truth, and his grave is widened and lit for him. A hadith in al-Tirmidhi names the two angels Munkar and Nakir.
The disbeliever or hypocrite answers each question with "I don't know", and his grave becomes narrow and a place of punishment. The Quran points to this: Allah keeps the believers firm with the firm word in this life and the next (14:27), and the Prophet ﷺ explained that this verse is about the questioning in the grave.
The punishment of the grave is real. The Quran says the people of Pharaoh are exposed to the Fire morning and evening, before the Day of Judgement (40:46). The Prophet ﷺ taught us to seek refuge from it in every prayer, before the salam: "O Allah, I seek refuge in You from the punishment of Hell and from the punishment of the grave."
These answers cannot be memorised and recited on the day. A person answers with what he truly lived by. So the way to prepare is to know Allah, practise Islam and follow the Prophet ﷺ now. Read more in Barzakh and the afterlife.
The evidence
Quran, Surah Ibrahim 14:27
يُثَبِّتُ ٱللَّهُ ٱلَّذِينَ ءَامَنُوا۟ بِٱلْقَوْلِ ٱلثَّابِتِ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَفِى ٱلْءَاخِرَةِ ۖ وَيُضِلُّ ٱللَّهُ ٱلظَّٰلِمِينَ ۚ وَيَفْعَلُ ٱللَّهُ مَا يَشَآءُ ﴿٢٧﴾
Allah keeps firm those who believe, with the firm word, in worldly life and in the Hereafter. And Allah sends astray the wrongdoers. And Allah does what He wills.
Explained in hadith as Allah keeping the believer firm when questioned in the grave.
Quran, Surah Ghafir 40:46
ٱلنَّارُ يُعْرَضُونَ عَلَيْهَا غُدُوًّۭا وَعَشِيًّۭا ۖ وَيَوْمَ تَقُومُ ٱلسَّاعَةُ أَدْخِلُوٓا۟ ءَالَ فِرْعَوْنَ أَشَدَّ ٱلْعَذَابِ ﴿٤٦﴾
The Fire, they are exposed to it morning and evening. And the Day the Hour appears [it will be said], "Make the people of Pharaoh enter the severest punishment."
Shows punishment before the Day of Judgement, in barzakh.
Sunan Abi Dawud 4753
Graded sahih... مَنْ رَبُّكَ فَيَقُولُ رَبِّيَ اللَّهُ فَيَقُولاَنِ لَهُ مَا دِينُكَ ...
"Who is your Lord? He says: My Lord is Allah. They say to him: What is your religion?"
Gives the questions asked in the grave and the believer's answers.
Sahih al-Bukhari 4699
Sahih... الْمُسْلِمُ إِذَا سُئِلَ فِي الْقَبْرِ يَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ ...
"When the Muslim is questioned in the grave, he testifies that there is no god but Allah and that Muhammad is the Messenger of Allah."
Links 14:27 to the questioning in the grave.
Sahih Muslim 588
Sahih... اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنْ عَذَابِ جَهَنَّمَ وَمِنْ عَذَابِ الْقَبْرِ ...
"O Allah, I seek refuge in You from the punishment of Hell and from the punishment of the grave."
The Prophet taught this refuge in every prayer, showing the punishment of the grave is real.
Where the ruling is recorded
- al-Fiqh al-Akbar (Imam Abu Hanifa), Section on the grave. States that the questioning of Munkar and Nakir and the punishment of the grave are true.
- al-Aqida al-Tahawiyya, Section on the grave. Affirms the questioning in the grave and that the grave is a garden of Paradise or a pit of the Fire.
This answer is pending review by the scholars on our team. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.