The expansion or constriction of the grave, its light, verdure, or flames are in no way of the same order as the things we know in this world.
Allah—exalted is He—has only allowed the children of Adam, while they dwell in this abode, to witness what belongs to it and originates within it. As for the affairs of the Hereafter, He has cast a veil over them so that acknowledging them in faith becomes the very cause of their felicity. When that veil is lifted, those realities will be seen with the eye. Thus, even if the deceased were lying among living people, nothing would prevent the two angels from coming to him and questioning him without those present being aware; he could answer them without their hearing his words, and they could strike him without their seeing the blows. One of us may sleep beside a fully awake companion, yet in his sleep be tormented, beaten, and made to suffer pain while the waking companion knows absolutely nothing of it.
Shaykh al-Islām Ibn Taymiyyah (d. 728 AH) said: “The hadiths concerning the punishment of the grave and the questioning by Munkar and Nakir are numerous and mutawātir from the Prophet ﷺ. Among them is what is recorded in the two Ṣaḥīḥs from Ibn ʿAbbās: ‘The Prophet ﷺ passed by two graves and said, “They are certainly being punished, though they are not being punished for something people consider great—indeed, it is great: one of them used to spread malicious gossip, and the other did not keep himself from his urine.” He then asked for a fresh palm-branch, split it in two, and placed a half on each grave. The people said, “Messenger of Allah, why did you do that?” He replied, “Perhaps their punishment will be lightened for them so long as these remain fresh.”’
“In Ṣaḥīḥ Muslim and the other Sunan collections it is also narrated from Abū Hurayrah that the Prophet ﷺ said: ‘When any one of you has finished the final tashahhud, let him seek refuge in Allah from four things: from the punishment of Hell, from the punishment of the grave, from the trial of life and death, and from the trial of the False Messiah.’ ”
The Shaykh then cited many other hadiths on this topic and concluded: “Reports from the Messenger of Allah ﷺ establishing the torment and bliss of the grave for those who deserve them, and the questioning by the two angels, have reached the level of tawātur. It is therefore obligatory to affirm them and believe in them, without delving into the manner of their occurrence, for it is not…"