The reciter: And Yahya ibn Bukayr narrated to us, saying: Ya'qub ibn 'Abd al-Rahman narrated to us from Abu Hazim, who said: I heard Sahl ibn Sa'd say: I heard the Prophet (peace and blessings be upon him) say:
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.
أنا فرطكم على الحوض من ورده شرب منه ومن شرب منه لم يظمأ بعده أبدا ليرد علي أقوام أعرفهم ويعرفوني ثم يحال بيني وبينهم Sahih al-Bukhari 7050. Abu Hazim said: Al-Nu'man ibn Abi 'Iyash heard me narrating this to them, so he said: "Is this how you heard Sahl say it?" I said: "Yes." He said: "And I bear witness to Abu Sa'id al-Khudri, for I heard him add to it:
I will say those people are from me. It will be said, 'You do not know what changes and new things they did after you.' Then I will say, 'Far removed (from mercy), far removed (from mercy), those who changed (the religion) after me!
إنهم مني فيقال إنك لا تدري ما بدلوا بعدك فأقول سحقا سحقا لمن بدل بعدي Sahih al-Bukhari 7051.