Musnad Abu Ya'la al-Mawsili 109:55

Abu Hammam narrated to us, Ibn Wahb narrated to us, he said: Amr ibn al-Harith informed me, from Abu al-Zubayr, from Jabir, that he said: "O Messenger of Allah, do we act for a matter that has already been finished, or for a matter that we are just beginning?" He said: "For a matter that has already been finished." Suraqah ibn Malik said: "Then why act, if so?" The Messenger of Allah (peace and blessings of Allah be upon him) said: "Everyone is facilitated for his work."