We often imagine personal holiness is a ladder climb through this life, each day we take one more step heavenward. The reality is that for most of us it doesn’t work this way. Sanctification is played out in the fierce struggle between flesh and spirit, requiring all our Spirit-given exertion just to stand firm in one place without falling. Not to mention, on top of this, our ultimate glorification is tied to our faithful endurance during personal suffering (Rom. 8:17, 2 Cor. 1:5, Phil. 3:10).

Sanctification is no simple topic. And the most carefully balanced study of personal renewal (or progressive sanctification) that I have read is David Peterson’s Possessed by God: A New Testament Theology of Sanctification and Holiness (IVP, 1995). In it he firmly roots his study of progressive sanctification in the finished work of the Savior and in our union with Christ. Notice the carefulness with which he explains the path of personal renewal in its various forms.

He writes on pages 91–92:

The challenges to holiness examined in this chapter convey both warning and encouragement. No Christian should doubt the need to give practical, everyday expression to the holiness that is our status and calling in Christ. Only those who trust in his sanctifying work on the cross, and take seriously the warning to ‘pursue holiness’, will ‘see the Lord.’ …

On the other hand, it is possible to be so zealous for ‘progress’ that one’s attention shifts from God’s grace to human effort. Moral growth and development will be God’s gift to us at different stages of our lives, but spiritually must not be measured in terms of the rate of change. We are to go on exhibiting what we know of God’s character and will, motivated by the certainty of his acceptance, cleansing and enabling in Christ, together with the promise of entire sanctification when we meet him, face to face. Progress may be seen as we exercise ourselves in that godly devotion which issues from a true knowledge of God in Jesus Christ.

These gospel perspectives on the Christian life must not be obscured by the uncertainty of a moralisic perfectionism. Scripture emphasizes that holiness is a divine gift – a share in the life and character of God. In practical, everyday terms it means being dedicated to God and separated from all that is sinful. This condition need to be renewed and re-expressed every day, especially when testing comes or fresh challenges to please God confront us.

And then later, in the conclusion to the book, he writes this on page 136:

Although the language of glorification may be used to speak of the Spirit’s present work in our lives (e.g. 2 Cor. 3:18), the New Testament offers no simple picture of daily progress to future glory. Flesh and Spirit are locked in a conflict that does not always see victory going to the one side. We are presently being conformed to Christ’s sufferings so that we might share with him in the ultimate transformation of resurrection. (136)

Those are wise and balanced words from a book to help a pilgrim like me who struggles to understand that sometimes merely standing firm and enduring is itself supernatural progress along the path to glorification.