Narrated 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." Abu Hazim added: An-Nu`man bin Abi `Aiyash, on hearing me, said. "Did you hear this from Sahl?" I said, "Yes." He said, " I bear witness that I heard Abu Sa`id Al-Khudri saying the same, adding that the Prophet said: 'I will say: They are of me (i.e. my followers). It will be said, 'You do not know what they innovated (new things) in the religion after you left'. I will say, 'Far removed, far removed (from mercy), those who changed (their religion) after me." Abu Huraira narrated that the Prophet said, "On the Day of Resurrection a group of companions will come to me, but will be driven away from the Lake-Fount, and I will say, 'O Lord (those are) my companions!' It will be said, 'You have no knowledge as to what they innovated after you left; they turned apostate as renegades (reverted from Islam).
English reference: Vol. 8, Book 76, Hadith 585
