Sahih Bukhari Volume 8, Book 81, Hadith 6585

حَدَّثَنَا سَعِيدُ بْنُ أَبِي مَرْيَمَ، حَدَّثَنَا مُحَمَّدُ بْنُ مُطَرِّفٍ، حَدَّثَنِي أَبُو حَازِمٍ، عَنْ سَهْلِ بْنِ سَعْدٍ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ إِنِّي فَرَطُكُمْ عَلَى الْحَوْضِ، مَنْ مَرَّ عَلَىَّ شَرِبَ، وَمَنْ شَرِبَ لَمْ يَظْمَأْ أَبَدًا، لَيَرِدَنَّ عَلَىَّ أَقْوَامٌ أَعْرِفُهُمْ وَيَعْرِفُونِي، ثُمَّ يُحَالُ بَيْنِي وَبَيْنَهُمْ ‏"‏‏.‏

Narrated By Abu Hazim from Sahl bin Sa'd : The Prophet said, "I am your predecessor (forerunner) at the Lake-Fount, and whoever will pass by there, he will drink from it and whoever will drink from it, he will never be thirsty. There will come to me some people whom I will recognize, and they will recognize me, but a barrier will be placed between me and them."