Hadith: There is a gate in Paradise called Ar-Rayyān through which those who fast will enter on the Day of Judgment. No one else will enter through it

عَنْ ‌سَهْلٍ رَضِيَ اللهُ عَنْهُ عَنِ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ:
«إِنَّ فِي الْجَنَّةِ بَابًا يُقَالُ لَهُ الرَّيَّانُ، يَدْخُلُ مِنْهُ الصَّائِمُونَ يَوْمَ الْقِيَامَةِ، لَا يَدْخُلُ مِنْهُ أَحَدٌ غَيْرُهُمْ، يُقَالُ: أَيْنَ الصَّائِمُونَ، فَيَقُومُونَ لَا يَدْخُلُ مِنْهُ أَحَدٌ غَيْرُهُمْ، فَإِذَا دَخَلُوا أُغْلِقَ، فَلَمْ يَدْخُلْ مِنْهُ أَحَدٌ».
[صحيح] - [متفق عليه] - [صحيح البخاري: 1896]

Sahl (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said:
"There is a gate in Paradise called Ar-Rayyān through which those who fast will enter on the Day of Judgment. No one else will enter through it. It will be called out: Where are those who fast? They will stand up. No one else will enter through it. Once they have entered, it will be closed, and no one will enter through it."
[Authentic hadith] - [Narrated by Bukhari & Muslim] - [Sahih Bukhari - 1896]

Explanation

The Prophet (may Allah's peace and blessings be upon him) informed that one of the gates of Paradise is called Ar-Rayyān, through which those who fast will enter on the Day of Judgment. No one else will enter through it. A call will be made: Where are those who fast? They will rise and enter, and no one else will be allowed to pass through it. Once the last of them has entered, it will be closed, and no one will enter through it thereafter.

Benefits from the Hadith

1. An-Nawawi said: This Hadīth denotes the merit of fasting and the honor bestowed upon those who fast.
2. Allah has designated a special gate among the eight gates of Paradise for those who fast, which will be closed after they enter.
3. Clarifying the fact that Paradise has gates.
4. As-Sindi said: His statement (where are those who fast) refers to those who frequently observe fasting, like the just person and the oppressor; it is said for those who are accustomed to this, not for someone who does so only once.
5. (Ar-Rayyān) means "the one that quenches thirst," because those who fast often experience thirst, especially during the long, hot days of the summer. So as a reward for them, this gate is called by something unique to them, the Gate of Ar-Rayyān. It is also said that Ar-Rayyān is derived from the form "fa‘lān", indicating abundance in quenching, the opposite of thirst. It was named to reward those who endure thirst and hunger during fasting.