AZABU L-QABR-Islamic theory of ‘Punishment of the grave’

The Prophet of God said, When a corpse is placed in its grave, two black angels come to it, with blue eyes. The name of the one is Munkar and of the other Nakīr, and they interrogate the dead person concerning the Prophet of God. If he be a Muslim, he will bear witness to the Unity of God and the mission of Muḥammad.