It is the consistent witness of the New Testament that growth in godliness requires exertion on the part of the Christian. Romans 8:13 says by the Spirit we must put to death the deeds of the flesh. Ephesians 4:22 instructs us to put off the old self and put on the new. Ephesians 6 tells us to put on the full armor of God and stand fast against the devil. colossians 3:5 commands us to put to death what is earthly in us. 1 Timothy 1:12 urges us to fight the good fight. Luke 13:24exhorts us to strive to enter the narrow gate.
Kevin rightly affirms the fact that the Christian life is not effortless-"let go and let God" is not biblical. Sanctification is not passive but active. My concern here is to add to what Kevin wrote and identify the direction of our effort.
There is no question that Christian's are to "work out our salvation with fear and trembling" (Philippians 2:12) and that the sanctification process will be both bloody and sweaty. After all, daily Christian living is daily Christian dying. Jesus likened the pain of Christian growth to "gouging out an eye" and "cutting off a hand"-indicating that growth in godliness requires parting with things we initially think we can't do without.
There does seem to be some question, though, with regard to the nature and direction of our efforts. And at the heart of this question is the relationship between justification and sanctification.
Many conclude that justification is step one and that sanctification is step two and that once we get to step two there's no reason to go back to step one. Sanctification, in other words, is commonly understood as progress beyond the initial step of justification. But while justification and sanctification are to be clearly separated theologically, the Bible won't allow us to separate them essentially and functionally. For example, citing 2 Peter 1:5, Kevin refers to the list of character traits that mark a Christian-faith, virtue, knowledge, self-control, steadfastness, godliness, brotherly affection, and love. Notice, though, what Peter goes on to say in 2 Peter 2:9:
For whoever lacks these qualities is so nearsighted that he is blind, having forgotten that he was cleansed from his former sins.
In her book because he loves me, Elyse Fitzpatrick rightly says:
One reason we don't grow in ordinary, grateful obedience as we should is that we've got amnesia; we've forgotten that we are cleansed from our sins. In other words, ongoing failure in our growth is the direct result of failing to remember God's love for us in the gospel. If we fail to remember our justification, redemption, and reconciliation, we'll struggle in our sanctification.
In other words, remembering, revisiting, and rediscovering the reality of our justification every day is the hard work we're called to do if we're going to grow.