Musnad Ahmad 30:2738

Hajjaj narrated to us, he said: Layth narrated to us, he said: Yazid ibn Abi Habib narrated to me, from 'Arak, from Abu Hurayrah, that he heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Indeed, among the worst of people is the two-faced person, who comes to these with one face, and to these with one face."