Musannaf Ibn Abi Shayba 33:142

Affan narrated to us, he said: Abd al-Rahman ibn Ibrahim narrated to us, he said: al-Ala’ narrated to us, from his father, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Indeed, the religion began as something strange, and it will return as it was. So glad tidings to the strangers."