Though outwardly we are wasting away, yet inwardly we are being renewed day by day. Paul is honest here: The outer is getting weaker. But the inner, the new person in Christ, is renewed daily.
In the New Covenant it is not about being outwardly perfect. It is about the inner renewal God works every day. You do not grow tired because you give up, you are renewed because God does not stop.
Today you can receive this daily renewal.