An Unarmed Adversary

As always - this is my own wondering and learning.  Take everything as something to think about...

In the cross we were given victory over sin.  That means that it has no power over us.
However, Satan is still free to challenge and tempt us during our time in this world.
This means that he has been given the ludicrous task of challenging us in a game that both he and we know that he cannot win.  So what is his motivation, and what is his strategy?
I can only surmise that his only goal is to render us ineffective.  He knows we have been won and he has no chance of overcoming us, but he can minimize or even eliminate our impact toward saving others.
And how can he do so - when we know that we have power over him?
The best way I can wrap my head around it is to think of playing poker.  In every hand we are told (truthfully) that we have a winning hand.  This leaves Satan with only two strategies: deception and distraction.  Those are the only tricks he's got.  And yet we fall for it over and over.
We both know we've got him licked, but his only chance is to get us to fold, or at the very least, to keep us so wrapped up in wondering what cards he is going to play that he keeps us from quickly scooping up all of his chips and moving on to better things.
It's a bit simplistic, but I think it can help the next time you feel as if you're being tempted beyond what you can handle.  Remember that the Devil is a two-trick pony - he's either bluffing or trying to pull your attention away from serving Jesus.  He's already lost - there's nothing else he can do.  So quickly figure out which one it is, call him on his cards, and get on to doing the work that Christ has set out for you.
The game is already won.