Musnad Ahmad 33:823

Abu Nu'aym narrated to us, Sufyan narrated to us, from Abu al-Zubayr, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Iblis has despaired that the worshippers will worship him, but [he is active] in inciting discord among them." Waki' narrated it to us, from Sufyan, with the same meaning.