Munkar and Nakir (Arabic: منكر و نكير) (English translation: "The Denied and The Denier") in Islamic eschatology, are angels who test the faith of the dead in their graves.
These angels are described as having solid black eyes, having a shoulder span measured in miles, and carrying hammers "so large, that if all of mankind tried at once to move them a single inch, they would fail". When they speak, tongues of fire come from their mouths. If one answers their questions incorrectly, one is beaten every day, other than Friday, until Allah gives permission for the beating to stop.
Muslims believe that after a person dies, his soul passes through a stage called barzakh, where it exists in the grave (even if the person's body was destroyed, the soul will still rest in the earth near their place of death). The questioning will begin when the funeral and burial is over. Nakir and Munkar prop the deceased soul upright in the grave and ask three questions: "Who is your Lord? What is your religion? What is your faith about this person (Muhammad)?". A righteous believer will respond correctly, saying that their Lord is Allah, that Muhammad is their prophet and that their religion is Islam. If the deceased answers correctly, the time spent awaiting the resurrection is pleasant. Those who do not answer as described above are chastised until the day of judgment.
Muslims believe that a person will correctly answer the questions not by remembering the answers before death (compare with the Egyptian Book of the Dead) but by their iman and deeds such as salat and shahadah (the Islamic profession of faith).