“Indeed, in Paradise there is a gate called al-Rayān. The fasting people will enter through it on the Day of Resurrection; none will enter with them besides them. It will be announced: ‘Where are the fasting ones?’ So they will rise and enter through it. When the last of them has entered, it will be closed, and no one else will enter through it.”

Narrated by al-Bukhārī (1896) and Muslim (1152) — and the wording is his — from the ḥadīth of Sahl ibn Saʿd — may Allah be pleased with him.
And it is also reported from him by al-Tirmidhī (765), al-Nasāʾī (2557), and Ibn Mājah (1640): “…and whoever enters it shall never thirst again.”
Authenticated in Ṣaḥīḥ al-Jāmiʿ (4241) and Ṣaḥīḥ al-Targhīb wa al-Tarhīb (979).

Brief Explanation of the Hadith

Fasting is a tremendous act of worship that combines sincerity and patience, and it is among the most excellent means by which a servant draws near to his Lord. Numerous aḥādīth have come clarifying its virtue and the greatness of its reward. Among them is what Sahl ibn Saʿd — may Allah be pleased with him — narrated, that the Prophet — may Allah’s peace and blessings be upon him — said: “Indeed, in Paradise there is a gate called al-Rayyān…”
This ḥadīth indicates the nobility of fasting and the lofty status of those who fast in the sight of Allah, Exalted is He. He has singled them out with a gate among the gates of Paradise through which they alone will be called — the gate of al-Rayān, derived from al-rayy (quenching of thirst), which is the opposite of thirst. This is in recompense for the thirst they endured in the world out of obedience to Allah.
It was given this name because those who enter through it shall be quenched and will never experience thirst again, as mentioned in some narrations: “Whoever enters it will never thirst thereafter.” This signifies the perfection of bliss and the completion of comfort after the toil and hardship of fasting. Thus, this blessed group will be called forth — before all of creation — with a call of honor and ennoblement: “Where are the fasting ones?” Where are those who persevered in obedience and abandoned their desires for the sake of their Lord? They will rise, honored and distinguished, and they will enter Paradise through a gate shared by none besides them. Then the gate will be closed — magnifying their exclusivity and the exaltedness of their rank.
This gate is one of the eight gates of Paradise that have been opened for the people of obedience. Allah has assigned to each act of devotion a gate particular to it: the Gate of al-Rayān is for the people of fasting; the gate of prayer is for the people of humility and devotion; the gate of charity is for the people of generosity and beneficence; and the gate of jihād is for those who sacrifice and strive. Thus, this is part of the perfection of the recompense and justice— for Allah honors every servant in accordance with his obedience and sincerity.
The ḥadīth contains a momentous glad tidings for sincere fasting people, and an indication of the lofty rank of fasting in the scale of deeds. It is also an encouragement to remain constant upon fasting — in Ramaḍān and beyond — in hope that the servant may be among those who enter through the Gate of al-Rayyān into the Gardens of Bliss.