Musnad Ahmad 1034:191

'Abd al-Razzaq narrated to us, Bakkar narrated to us, Khallad ibn 'Abd al-Rahman narrated to me, that he heard Abu al-Tufayl narrating that he heard Hudhayfah ibn al-Yaman saying: "O people, will you not ask me? For people used to ask the Messenger of Allah, peace and blessings of Allah be upon him, about the good, and I used to ask him about the evil. Indeed, Allah sent His Prophet, peace and blessings of Allah be upon him, and he called the people from disbelief to faith, and from misguidance to guidance. So, those who responded to him responded, and that which was dead of the truth became alive, and that which was alive of falsehood died. Then Prophethood departed, and there was the Caliphate upon the methodology of Prophethood."