You will notice in Ephesians 6:10-14 that we are exhorted to stand 4 times in regard to our walk with God and our resisting of the Devil. We need to constantly remind ourselves that we are in a war in which the battle has been won already. The epistles show us that Satan was defeated at the cross but he is still around and will only finally be eradicated when he is thrown into the Lake of Fire after Jesus returns.