“The saying is trustworthy, for: 

     If we have died with him, we will also live with him;

     if we endure, we will also reign with him;
     if we deny him, he also will deny us;
     if we are faithless, he remains faithful—
     for he cannot deny himself.”
          – 2 Timothy 2:11-13
In reference to maturation, I would rather establish the sort of language by which we speak of being grown into maturity, as opposed to us growing ourselves into it. In directly relating the concept of, say, maturing in purity, or maturing in holiness, or “growing” out of addiction and slavery, the apostle Paul first connects any work of ours to a work done outside of us – namely, the work of Jesus at the cross. 
Simply put: grace fuels growth. “For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them” (Eph 2:10 ESV). Then, in Philippians, the last of Paul’s prison epistles, he encourages the believers with the assurance that Christ would complete the good work he began in them. 
The best way that we can address growth in maturity and behavioral change is to establish that, “If any man be in Christ, he is a new creation” (2 Cor 5:17). It is interesting toi me that we want so badly to take credit for the progress made in life, as though we were capable of good on our own, when scripture tells us we are bound by a law of sin and death.

Because of Jesus, we are no longer bound to that law. 

Because of the work of the Son of God on the cross, we are no longer bound to that law.
The gospel works in our hearts a growing obedience birthed in love and gratitude for the undeserved work done on our behalf. 
Consider this excerpt from Richard Ross, cofounder of the True Love Waits organization, on premarital purity, as I think it sums up the idea nicely:
“The [purity] promise is kept most tenaciously by teenagers who have moved beyond moralistic therapeutic deism and who adore the King of Kings with awe and intimacy. They know their Lord and Savior said, “If you love me, you will keep my commandments.” Their walk in purity is a way to express deep love for him and to respond to his supremacy. For teenagers who know Christ, that is a far stronger motivator than a desire to avoid disease and pregnancy.
Risk avoidance is a weak motivator during adolescence, since the development of the brains prefrontal cortex (which governs self-control) lags well behind the development of the amygdala (which drives emotions and impulses). Teenagers need to know about the risks of promiscuity, as well as about the benefits that total life purity brings. But the most powerful way to impact prom-night decisions is for parents, leaders and peers to more fully awaken teenagers to God’s Son.”  
This truth applies to our closet-secrets, as well. Be it prom-night or porn-night, tf grace is not the motivator for and enabler of change, then any progress we make toward or away from something will be the fuel for pride in seasons of success, or condemnation as the result of failure – neither of which are fitting for sons and daughters of the King of kings. We need someone outside of ourselves to tell us who we are, “for it is God who works in you, both to will and to work for his good pleasure” (Phil 2:13). Personally, it is a more freeing thing to know that the Holy Spirit is at work within me to change my very desires than it is to rely on my own power to modify them. 
“What the heart loves, the will chooses, and the mind justifies.” – Ashley Null
Of my own volition, I will justify my choices to indulge in the sin that my heart loves. I need a new love. We need a new, Capital-“L”-Love to pursue with as much ferocious abandon as we once pursued “the sinful desires of [our] hearts” (Rom 1:24). Let’s run full-forced towards Jesus because of the grace by which we are enabled to do so, and allow the characteristics and responsibilities of growing in maturity to be added to us as a joy in which we are able to participate, instead of a burden by which we seek to curb our appetites. 
We are no more free curbing our appetites constantly in the back of our minds than we are indulging in them. By the power of Christ we may develop new appetites which put sin to death as Paul envisioned. By the grace of Christ we may love and allow our growth to be it’s overflow.
“We love because he first loved us.” – 1 John 4:19
Thank you, Jesus, for being faithful, even in our times of faithlessness. Make us more like you.