Sunan At-Tirmidhi

Narrated Abu Hurairah: That the Messenger of Allah (ﷺ) said, ""I was shown the first of (every) three to enter Paradise: A martyr, an 'Atif, who is a Muta'affif, and a slave who perfected his worship of Allah, and was sincere to his masters."" [Abu 'Eisa said:] This Hadith is Hasan