Musnad Ahmad 33:146

Hashim narrated to us, [he said] Ali bin Zaid informed us, from Muhammad bin al-Munkadir, from Jabir, that Suraqah bin Malik said: "O Messenger of Allah, regarding what is the action? Is it in something that has already been finished, or in something we are just beginning?" He said: "Rather, it is in something that has already been finished." He said: "Then why act, if so?" He said: "Act, for everyone is facilitated for that which he was created for."