Musnad Ahmad 30:1475

Hassan ibn Musa narrated to us, Ibn Lahi'ah narrated to us, Salaman ibn Amir narrated to us, from Abu Uthman al-Asbahi, who said: I heard Abu Hurairah saying: Indeed, the Messenger of Allah, may Allah bless him and grant him peace, said: "There will be in my nation impostors and liars who will bring you novelties of speech, with that which neither you nor your fathers have heard. So beware of them, lest they lead you into tribulation."