The Messenger of Allah ﷺ said, "In Paradise there are one hundred levels, and between each two levels is a distance like that between the heavens and the earth. Firdaws is the highest level, from it gush forth the four rivers of Paradise, and above it is the Throne. So when you ask Allah, ask Him for Firdaws."
أن رسول الله ﷺ قال: في الجنة مائة درجة ما بين كل درجتين كما بين السماء والأرض. والفردوس أعلاها درجة، ومنها تفجر أنهار الجنة الأربعة، ومن فوقها يكون العرش، فإذا سألتم الله فسلوه الفردوس.
Tirmidhi (2531) narrated it from Abdullah bin Abdul-Rahman, who said, Yazid bin Harun told us, Hammam told us, Zayd bin Aslam told us, from Ata bin Yasar, from Ubada bin Samit, and he related it. Its chain is sahih. Ibn Khuzayma and Hakim also graded it sahih.The hadith was narrated by Imam Ahmad (22695) from Yazid, that is, Ibn Harun, and it contains, "Between each two levels is a distance of a hundred years." The wording given by Tirmidhi was also narrated by Imam Ahmad from Affan bin Muslim, from Hammam. Through this same route it was also narrated by Ibn Khuzayma in Tawhid (184), and by Hakim (1/80), who said, "Its chain is sahih."As for what is reported from Muaz bin Jabal, that the Messenger of Allah ﷺ said, "Whoever fasts Ramadan, performs the prayers, and makes pilgrimage to the House, I am not sure whether zakat was mentioned or not, it is a duty upon Allah to forgive him, whether he emigrated for His sake or remained in the land where he was born." Muaz said, "Shall I not inform the people of this?" The Messenger of Allah ﷺ said, "Leave the people to their deeds, for in Paradise there are a hundred levels, and between each two levels is a distance like that between heaven and earth. Firdaws is the highest part of Paradise, and its middle, and above that is the Throne of the Merciful, and from it the rivers of Paradise burst forth. So when you ask Allah, ask Him for Firdaws." This is daif.It was narrated by Tirmidhi (2530) and Ibn Majah (4331), both by way of Zayd bin Aslam, from Ata bin Yasar, from Muaz bin Jabal, but Ata bin Yasar never met Muaz bin Jabal. Tirmidhi said, "Ata never met Muaz bin Jabal. Muaz died long ago, in the caliphate of Umar." However, he also said, "This, in my view, is more sahih than the hadith of Hammam, from Zayd bin Aslam, from Ata bin Yasar, from Ubada bin Samit."I say, there is something questionable in this last statement of his, because Hammam bin Yahya is trustworthy, among the narrators relied upon by the two sheikhs, so being contradicted by others does not harm him, since he related it correctly. Likewise, Hilal bin Ali narrated it, from Ata bin Yasar, from Abu Hurairah, as mentioned earlier in Sahih Bukhari. So it is more fitting to judge those who contradict them as being in error and anomalous.