Sahih al-Bukhari 7050
Narrated Sahl bin Sa`d:
I heard the Prophet (ﷺ) saying, "I am your predecessor at the Lake-Fount (Kauthar), and whoever will 
come to it, will drink from it, and whoever will drink from it, will never become thirsty after that. 
There will come to me some people whom I know and they know me, and then a barrier will be set up 
between me and them."
حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا يَعْقُوبُ بْنُ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي حَازِمٍ، قَالَ سَمِعْتُ سَهْلَ بْنَ سَعْدٍ، يَقُولُ سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ ‏
"‏ أَنَا فَرَطُكُمْ، عَلَى الْحَوْضِ، مَنْ وَرَدَهُ شَرِبَ مِنْهُ، وَمَنْ شَرِبَ مِنْهُ لَمْ يَظْمَأْ بَعْدَهُ أَبَدًا، لَيَرِدُ عَلَىَّ أَقْوَامٌ أَعْرِفُهُمْ وَيَعْرِفُونِي، ثُمَّ يُحَالُ بَيْنِي وَبَيْنَهُمْ ‏"‏‏.‏