Narrated Al-Bara’ b. ‘Azib reported the Prophet as saying, “When a Muslim is questioned in the grave he testifies that there is no god but God and that Muhammad is God’s messenger.” That is verified by God’s words, “God establishes those who believe with the word that stands firm in this world and the next.”:
“God establishes those who believe with the word which stands firm” was revealed concerning the punishment in the grave. One will be asked who his Lord is and will reply that his Lord is God and his prophet is Muhammad.
Umm Salama said, “Messenger of God, you continue to be afflicted annually with pain from the poisoned sheep you ate.” He replied, “I am afflicted by nothing due to it which was not decreed for me while Adam was still a lump of clay.”
Anas reported God’s messenger as saying, “When a man is placed in his grave and his friends leave him, he hears the beat of their sandals. Then two angels come to him and, having made him sit up, they say, ‘What was your opinion of this man, of Muhammad?’ The believer replies, ‘I testify that he is God’s servant and messenger.’ He is then told to look at his abode in hell for which God has substituted for him an abode in paradise, and he sees them both. The hypocrite and infidel are asked, ‘What was your opinion of this man?’ and reply, ‘I do not know; I held the opinion others held.’ They will retort, ‘You neither knew nor did you follow .’ He will then be given a blow with iron hammers and will utter a shout which will be heard by all who are near him, with the exception of men and jinn.”
While we were with God’s messenger discussing what would come to pass God’s messenger said, “When you hear that a mountain has moved from its place believe it; but when you hear that a man's nature has changed do not believe it, for he will remain true to his inborn disposition.”