Musnad Ahmad 1013:76

Hashim ibn al-Qasim narrated to us, Abd al-Rahman—meaning Ibn Abd Allah ibn Dinar—narrated to us, from Abu Hazim, from Sahl ibn Sa’d, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I am your forerunner at the Basin (al-Hawd). Whoever comes to me shall drink, and whoever drinks shall never thirst again. I foresee that there will be people who come to me whom I recognize and who recognize me, then a barrier will be placed between me and them." He said: Then al-Nu’man ibn Abi ‘Ayyash heard me narrating this, and he said: "And I bear witness that Abu Sa’id al-Khudri adds to it, saying: And I will say: 'They are my nation, or from me.' It will be said: 'You do not know what they innovated after you, or what they changed after you.' So I will say: 'Away, away with those who changed after me.'"