There is a phrase in Ephesians that doesn't occur anywhere else in the Bible.  Ephesians 2:1-2 "God quickened (made alive) those of you who were dead in trespasses and sins.  You used to walk according to the course of this world, according to the prince of the power of the air, (that's the phrase) the same spirit that now works in the children of disobedience."

There are two spiritual forces at work in humans.  Good, and evil.  Paul calls this evil force (Satan) a prince of the air.  It is all around us, and within us.  Think of it this way:  If you have children, you know for a fact that you never had to teach them to do wrong.  You spent their entire childhood trying to teach them to do good.  We are, by nature, (born) inclined to do wrong.  It must be fought.

Don't bite.  Don't spit.  Don't steal.  Don't lie.  And on and on.  It takes constant instruction to teach a child to "Do unto others as you would that they should do unto you."  Which is basically one of the two natural laws of God.  "Love the Lord with all your heart, and love your neighbor as yourself."  Left to themselves, children grow up into self centered brats.  Every elementary school teacher will attest to the fact that learning "goodness" begins in the home.  It's almost impossible to straighten a child out that has been raised in a home of "badness."

This "Prince of the Power of the air," that Paul talks about is what the Bible calls the natural inclination of man--a force, Satan, that has great power to destroy us.  It also indicates that we should, "Be sober, be vigilant; because your adversary the devil walks about as a roaring lion seeking whom he may devour.  (1Peter 5:8)  Paul says it one way; Peter says it another.

But we--Christians--have been "quickened."  We have been made alive.  We have been given the power of God within ourselves--His Holiness, His life.  "Christ in you, the hope of glory," which Paul said is a mystery that has now been made clear.  We have power to conquer evil.  We have the power to be what God wants us to be.  Without Jesus, you can't do it.  He is your holiness.  We become a Christ--ians when we repent and ask him to take control of our nature.

Every action movie uses these concepts.  Good versus evil.  Star Wars, Cinderella and the Seven Dwarves, etc.  We want the good to win.  We are on God's side.