Lest the beasts of the field become too numerous for you

I'm working on memorizing this passage in Deuteronomy, and thinking a lot about it as a description of normal Christian spiritual growth. (I am becoming very convicted about the end - the part about not bringing abominations into your house. What media am I allowing to have hold over my imagination? TV? books? internet? Hmm.)
The part that's really sticking out to me right now though is verse 22:
And the LORD your God will drive out those nations before you little by little; you will be unable to destroy them at once, lest the beasts of the field become too numerous for you.
It reminds me so much of that scary story Jesus tells in Matthew 12, about the demon who returns to the man he came out of, and finding his home unoccupied, reoccupies it, along with seven more spirits more wicked than itself.

The idea being - and I could be getting this wrong, I haven't studied this, and these are just my beginning thoughts on these verses - that as the Holy Spirit helps you clear out sinful habits in your life, He does it slowly, so that you have time to fill the space left by those sinful habits with virtuous habits.  If He just made you instantly sinless, if He - in the words of Deuteronomy - destroyed all the nations at once - you would be overwhelmed by the emptiness. The beasts of the field would be too numerous for you. Your house would be unoccupied, and who knows what would come to fill it?
Instead, He drives them out little by little, so you have time to grow into the empty space that is left.
BUT.
But don't forget the end of that passage:
But the LORD your God will deliver them over to you, and will inflict defeat upon them until they are destroyed.
And I like it even better in the King James, where it says he will destroy them with a mighty destruction, until they be destroyed.
I am fascinated by the juxtaposition of "I will do this slowly, so you are not overwhelmed" and "I will do this absolutely, because My holiness demands it." All at once He is aware of our limitations while being uncompromising about His nature. 

It gives me hope, as I look at my habitual sins, and even more, at my persistent immaturity (which is persistent because of my habitual sins), and am discouraged about how long it takes to get better at this, and dear Lord, will I ever get it right, ever be fit to see your face? to know that on the one hand, He is not unaware of my weakness and on the other, He will settle for nothing less than the absolute removal of all wicked ways from me.
When I am afraid my slow progress means I'm not making any progress, I'm encouraged to think that this is actually the way He wants it to be, because He knows that more would overwhelm me.
When I'm tempted to stop trying, because surely where I am is good enough, I am reminded that He is holy, and that I am not to allow any evil to have any hold over me.
I hope you're encouraged too, as you start another week, to turn your eyes upon Jesus, and to keep following. He won't let you fall, nor will He let you fall behind. Keep going.
peace of Christ to you,
Jessica Snell
p.s. Read Jeanne's post from last year on this passage here. She's the one who first got me thinking about this wonderful bit of scripture.