The Prophet ﷺ said, "In Paradise there is a gate called ar-Rayyan. On the Day of Resurrection it will be called out, 'Where are those who used to fast?' Whoever was among those who fasted will enter through it, and whoever enters it will never thirst again."
حدثنا عبد الرحمن بن إبراهيم الدمشقي حدثنا ابن أبي فديك حدثني هشام بن سعد عن أبي حازم
أن النبي ﷺ قال إن في الجنة بابا يقال له الريان يدعى يوم القيامة يقال أين الصائمون فمن كان من الصائمين دخله ومن دخله لم يظمأ أبدا
[Its isnad is hasan] Tirmidhi narrated it in the chapter on Fasting, in the section on the merit of fasting, no. 765, from the hadith of Hisham bin Saad through this route, and he said, hasan sahih ghareeb. Bukhari also narrated it, no. 1896, and Muslim, no. 1152, from the hadith of Abu Hazim through this route.