2 Peter 3:18
"but grow in the grace and knowledge of our Lord and Savior Jesus Christ."
I've been considering this verse lately, having friends on two sides of the spectrum.
Side one: the Self-Conscious Improver
This is the idealist. They might constantly set spiritual goals and meet them - in their own minds. Or they pat themselves on the back when they look back. "My marriage, devotional life, etc. has really improved since 10 years ago. I thank you, Lord, that I am not like other sinners." The danger of self-righteousness is pretty obvious, here. There's lots of emphasis on growth, but it's by our virtue and effort. People who grow up in the church know this is wrong, so layers of self-deception tend to build up. We tell ourselves it's by God's grace when inside we really believe it's because we've worked harder at it.
Side two: we're all stuck
This is the cynic. He denies we grow at all, or only very minimally. Goal setting is a bad idea to him. "I'm still struggling with the same issues in my marriage as 10 years ago. I'm a worm." The danger here is too little faith in the power of the Holy Spirit to overcome the sin in our lives. There's lots of emphasis on depravity and the sinful nature, but putting forth effort is seen as automatically legalistic. This option is accepted on the surface by many in the church. Who can argue against affirming sin and depravity in one's self? Worm theology is a very acceptable form of false humility.
The Bible calls us to grow. It also says it is God who works in us to work out our salvation. So let us pray for grace to grow in Christ's grace, BY His grace.
Here's John Calvin, with a better balance.
But no one in this earthly prison of the body has sufficient strength to press on with due eagerness, and weakness so weighs down the greater number that, with wavering and limping and even creeping along the ground they move at a feeble rate. Let each one of us, then, proceed according to the measure of his puny capacity and set out upon the journey we have begun. No one shall set out so inauspiciously as not daily to make some headway, though it be slight. Therefore, let us not cease so to act that we may make some unceasing progress in the way of the Lord. And let us not despair at the slightness of our success; for even though attainment may not correspond to desire, when today outstrips yesterday the effort is not lost. Only let us look toward our mark with sincere simplicity and aspire to our goal; not fondly flattering ourselves, nor excusing our own evil deeds, but with continuous effort striving toward this end: that we may surpass ourselves in goodness until we attain to goodness itself. It is this, indeed, which through the whole course of life we seek and follow. But we shall attain it only when we have cast off the weakness of the body, and are received into full fellowship with him. ((John Calvin, The Institutes of the Christian Religion (ed. John T. McNeill; trans. Ford Lewis Battles; 2 vols.; LCC; Philadelphia: Westminster Press, 1960), Book 3, Chapter 6, Section 5.)) - quoted here.