Jami` at-Tirmidhi Hadith 1071

The Messenger of Allah said: "When the deceased - or he said when one of you - is buried, two angels, black and blue (eyed_ come to him. One of them is called Al-Munkar, and the other An-Nakir. They say: 'What did you used to say about this man?' So he says what he was saying (before death) 'He is Allah's slave and His Messenger. I testify that none has the right to be worshipped but Allah and that Muhammad is His slave and His Messenger.' So they say: 'We knew that you would say this.' Then his grave is expanded to seventy by seventy cubits, then it is illuminated for him. Then it is said to him: 'Sleep.' So he said: 'Can I return to my family to inform them?' They say: 'Sleep as a newlywed, whom none awakens but the dearest of his family.' Until Allah resurrects him from his resting place.""If he was a hypocrite he would say: 'I heard people saying something, so I said the same; I do not know.' So they said: 'We knew you would say that.' So the earth is told: 'Constrict him.' So it constricts around him, squeezing his ribs together. He continues being punished like that until Allah resurrects him from his resting place."