John Bunyan's Holy War - Emmanuel's Last Charge to Mansoul

There are many fine things in Emmanuel's last charge to Mansoul, but by far the best thing is the answer that He Himself there supplies to this deep and difficult question,-to this question, namely, Why original sin is still left to rage in the truly regenerate? Nothing defiles and debases us but sin. Why, then, does He not take our sin clean out of us at once?