Musnad Ahmad 31:232

Sulayman ibn Dawud narrated to us, Abd al-Rahman ibn Abd Allah ibn Dinar narrated to us, from Abu Hazim, from al-Nu’man ibn Abi Ayyash al-Zuraqi, from Abu Sa’id al-Khudri, that the Prophet, peace and blessings of Allah be upon him, said: "Then I will say: 'My companions, my companions.' It will be said: 'You do not know what they innovated after you.' I will say: 'Away, away,' or he said: 'Perish, perish, for those who changed [the religion] after me.'"