Certainty of unseen reality

Sanctification is a constant reaccessing the Gospel of grace (the finished work of Christ) and applying it and reapplying it. The Gospel is not the ABC’s of the Christian life, but the A-Z’s of it as Tim Keller says and Tullian Tchividjian nails it here:

I’m currently preaching a series of sermons from the book of Colossians entitled Jesus+Nothing=Everything. It’s really a series on how the gospel sanctifies Christians. Over and over again I’m making the point that I used to think Christian growth happened as we go out and get what we don’t have–if we’re going to grow we have to go out and get more patience, get more strength, get more joy, etc. But after reading the Bible more carefully I’ve learned that Christian growth does not happen by working hard to get something you don’t have; Christian growth happens by working hard to live in the reality of what you do have.

You could say that Christian growth does not happen first by behaving better, but believing better–believing in bigger, deeper, brighter ways what Christ has already secured for sinners. In other words, the hard work of sanctification that Paul talks about in Philippians 2:12 is a continuous, daily going back to the reality of your justification.