Musnad Ahmad Hadith 22873

It is narrated from Sahl (may Allah be pleased with him) that I heard the Noble Prophet (ﷺ) saying: I will wait for you at the Pond of Kawthar. Whoever comes there will drink its water, and whoever drinks its water will never feel thirsty again. And some people will come to me whom I will recognize and they will recognize me, but then a barrier will be set up between them and me. Abu Hazim says that when Nu'man bin Abi Ayyash heard me narrating this hadith, he said: Did you hear Sahl (may Allah be pleased with him) saying it like this? I replied: Yes! He said: I bear witness regarding Abu Sa'id Khudri (may Allah be pleased with him) that I heard him narrate this addition: The Noble Prophet (ﷺ) will say: These are my followers. It will be said: You do not know what deeds they performed after you. I will say: Away with those people who changed my religion after me.