Praise be to Allah, and may peace and blessings be upon the Messenger of Allah.
The grave is the first stage of the Hereafter, which is why the Prophet ﷺ used to seek refuge with Allah from the trial and punishment of the grave. After a person is buried, the angels come to him and question him about his beliefs and faith.
It is authentically reported in the hadith of al-Bara' ibn 'Azib, may Allah be pleased with him, that the two angels ask the servant:
Who is your Lord?
The believer says: My Lord is Allah.
What is your religion?
He says: My religion is Islam.
Who is this man who was sent among you?
He says: He is the Messenger of Allah ﷺ.
The hadith also mentions that the believer will be enabled to answer correctly. A door to Paradise will be opened for him, and he will receive some of its fragrance and pleasant breeze. His grave will be expanded for him, and his righteous deeds will come to him in the form of a handsome man, with good clothing and a pleasant scent, who will give him glad tidings of what pleases him.
As for the disbeliever, or the one who is not enabled to answer correctly, he will say when questioned: “Hah, hah, I do not know.” Then a door to Hellfire will be opened for him, and he will receive its heat and poisonous fumes, and his grave will be constricted around him.
The Prophet ﷺ said in the hadith:
“Indeed, the grave is the first stage of the Hereafter. If one is saved from it, what comes after it will be easier; but if one is not saved from it, what comes after it will be more severe.”
Thus, it becomes clear that the three basic questions of the grave are:
Who is your Lord?
What is your religion?
Who is your Prophet?
Being saved from the trial of the grave does not come merely from memorizing the answers. Rather, it comes through affirming the Oneness of Allah, believing in Him, following His Messenger ﷺ, and acting upon that in this worldly life. A servant will be enabled to answer correctly in his grave according to the faith upon which he lived.
For this reason, one of the supplications of the Prophet ﷺ was:
“O Allah, I seek refuge in You from the trial of the grave and the punishment of the grave.”
We ask Allah to make us firm with the firm word in this world and in the Hereafter, and to save us from the trial and punishment of the grave.
And Allah knows best.