The Holy Qur'an always mentions Ayahs (verses) on reward and punishment coupled with mention of the Day of Judgment. For example, Allah says:
...on the Day of Resurrection they shall be consigned to the most grievous torment.
Allah also says:
Then (again), surely, you will be resurrected on the Day of Resurrection.
And other noble Ayahs speaking of the Day of Judgment. Now, is there any Ayah indicating that reckoning starts the moment a person is buried?
Reward and punishment are not always mentioned in contexts related to the Day of Judgment. Allah may hasten the punishment of some of His servants before death and may delay the punishment of others till the Day of Judgment. Allah (Exalted be He) says:
Whosoever desires the life of the world and its glitter, to them We shall pay in full (the wages of) their deeds therein, and they will have no diminution therein.
They are those for whom there is nothing in the Hereafter but Fire, and vain are the deeds they did therein. And of no effect is that which they used to do.
Allah also says:
Whoever desires the quick-passing (transitory enjoyment of this world), We readily grant him what We will for whom We like. Then, afterwards, We have appointed for him Hell; he will burn therein disgraced and rejected (- far away from Allâh’s Mercy).
In a further place Allah tells of His (Part No. 3; Page No. 467) help of
Musa (Moses, peace be upon him) against the disbelievers among his people:
So Allâh saved him from the evils that they plotted (against him), while an evil torment encompassed Fir‘aun’s (Pharaoh) people.
The Fire, they are exposed to it, morning and afternoon. And on the Day when the Hour will be established (it will be said to the angels): "Cause Fir‘aun’s (Pharaoh) people to enter the severest torment!"
These and other similar Qur'anic Ayahs denote that Allah may hasten the punishment of some people in this life or delay it until the Day of Judgment and may punish some in their graves like the case of
the people of Fir`awn (Pharaoh). May Allah grant us success. May peace and blessings be upon our Prophet
Muhammad, his family, and companions!