Sunan an-Nasa'i, Book 22, Hadith 147 (In-Book) ⓘ

It was narrated from Sahi bin Sad that the Prophet said: "For those who fast there is a gate in Paradise called Ar-Rayyan, through which no one but they will enter. When the last of them has entered it, it will be closed. Whoever enters through it will drink, and whoever drinks will never thirst again."

أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ أَنْبَأَنَا سَعِيدُ بْنُ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي حَازِمٍ، عَنْ سَهْلِ بْنِ سَعْدٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ لِلصَّائِمِينَ بَابٌ فِي الْجَنَّةِ يُقَالُ لَهُ الرَّيَّانُ لاَ يَدْخُلُ فِيهِ أَحَدٌ غَيْرُهُمْ فَإِذَا دَخَلَ آخِرُهُمْ أُغْلِقَ مَنْ دَخَلَ فِيهِ شَرِبَ وَمَنْ شَرِبَ لَمْ يَظْمَأْ أَبَدًا ‏" ‏ ‏.‏