Musnad Ahmad 2:115

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, and Hajjaj said: I heard Shu‘bah, from ‘Asim ibn ‘Ubayd Allah, from Salim, from Ibn ‘Umar, from ‘Umar: That he said to the Prophet, peace and blessings of Allah be upon him: "Do you see what we do in it—is it a matter already finished, or is it in something beginning, or an initiated matter?" He said: "In what has already been finished." ‘Umar said: "Shall we not then rely [upon it]?" He said: "Work, O son of al-Khattab, for everyone is facilitated. As for those who are among the people of felicity, they work for felicity; and as for the people of wretchedness, they work for wretchedness."