The Prophet ﷺ said, "In paradise there are one hundred levels which Allah has prepared for those who strive in His path. The distance between every two levels is like the distance between the heavens and the earth. So when you ask Allah, ask Him for Firdaws, for it is the middle of paradise and the highest part of paradise. Above it is the Throne of the Most Merciful, and from it the rivers of paradise burst forth."
عن النبي ﷺ، قال: إن في الجنة مائة درجة، أعدها الله للمجاهدين في سبيله، كل درجتين ما بينهما كما بين السماء والأرض، فإذا سألتم الله فسلوه الفردوس، فإنه أوسط الجنة، وأعلى الجنة، وفوقه عرش الرحمن، ومنه تفجر أنهار الجنة.
Bukhari narrated it in Tawhid (7423) from Ibrahim bin Munzir, who said, Muhammad bin Fulayh told me, who said, my father told me, Hilal told me, from Ata bin Yasar, from Abu Hurairah, and he mentioned it in a lengthy context.