Musnad Ahmad 907:18

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Simak ibn Harb, he said: I heard Jabir ibn Samurah, he said: I heard the Prophet, peace and blessings of Allah be upon him, saying: "Indeed, before the Hour, there will be liars." Simak said: And I heard my brother saying: Jabir said: "So beware of them."