Musnad Ahmad 384:2

Abdullah ibn Ahmad said: Abu Abdullah al-Basri narrated to us, Sahl ibn Aslam al-Adawi narrated to us, he said: Yazid ibn Abi Mansur narrated to us, from Dhu al-Lihya al-Kilabi, who said: I said: "O Messenger of Allah, do we act in a matter that is newly begun, or in a matter that has already been finished?" He said: "Rather, in a matter that has already been finished." He said: "Then why act?" He said: "Act, for everyone is facilitated for that which he was created for."