A few weeks ago I had the opportunity to interview John Piper. I promptly solicited questions from you, the readers of this site, and Pastor John was kind enough to answer them. Because the focus of this year’s Desiring God National Conference is sanctification, I asked him questions related to that subject. In this interview he discusses why sanctification is not an instantaneous act, how we can emphasize personal toil in holiness without diminishing the goodness and sovereignty of God, why we need to continue to confess our sins to God, and how we can know if we are growing in sanctification. If you read only one of the answers, be sure it is the final one!
What is God’s purpose in making sanctification a lifelong pursuit rather than an instantaneous act at the moment of conversion?
First, I agree with the assumption that this is true. God does do this. That is, he intentionally does not conquer all our sins in an instant, though he could. He could perfect us now. We know this because he is going to do it when we die. We will not sin in heaven. We will be among “the spirits of the righteous made perfect” (Heb. 12:23).
And we know that God will finally throw Satan into the lake of fire (Rev. 20:10) and take away his influence in the new world entirely. If he will do it then, he could do it now. But he doesn’t. He gives Satan leash. So why is Satan allowed to rage, and why does God let us go on stumbling toward holiness?
I am not aware of any text in the Bible that answers this question explicitly. So we answer with inferences from God’s broader statements of purpose. The largest answer is that God does all things for the greater display of his glory, and so this too must be for his glory.
One clue to make this more specific comes from Romans 9:22–23. Paul asks rhetorically, “What if God, desiring to show his wrath and to make known his power, has endured with much patience vessels of wrath prepared for destruction, in order to make known the riches of his glory for vessels of mercy?”