Shama-il Tirmidhi Chapter 34, Hadith Number 4 (219).
Abu Dhar radiyallahu anhu says, Rasoolullah sallallahu alaihe wasallam said, I know that person well who will enter Jannah first and also that person who will be the last one to be taken out of Jahannam. On the Day of Qiyaamah a person will be brought forward to the court of Almighty Allah. It shall be commanded that all the minor sins of that person be put forward to him and the major sign be concealed. When the minor sins are disclosed to that person, he will accept that he had committed them, as there will be no room for refuting them. (He will begin to tremble and say in his heart that these are only the minor sins, what will happen when the major sins are exposed.) During this happening it shall be commanded that for every sin of that person he be given the ajr (thawaab-reward) of a good deed. Upon hearing this person himself will say I still have many sins left to account for, that are not seen here.
Abu Dhar radiyallahu anhu says, Rasoolullah sallallahu alaihe wasallam while narrating the words of that person began laughing until his mubarak teeth began to show. (The reason being that the person himself disclosed the very sins he was frightened of.)
This person whose case is being narrated in detail is the same person of whom it was first described in brief that he will be the last one to enter Jannah, or it may be another person. The person who will enter Jannah last is the one whose incident is mentioned in the seventh hadith of this chapter.