Sahih Muslim Book 1, Hadith Number 374.

Chapter : The lowest of the ranks in Paradise.

Anas reported: The Messenger of Allah (may peace be upon him) said: The believers would gather on the Day of Resurrection, and they would be concerned about it, or would be made mindful of it (i.e. the trouble for it), (and the remaining part of the hadith would be narrated) like the one transmitted by Abu Uwana, and he said in the hadith: Then I would come for the fourth time, or I would return the fourth time, and would say: O my Lord, no one has been left but he whom the Holy Qur’an has restrained.