Yes, we are to grow in the Lord, we are to seek to become more Christ-like, putting on all the characteristics that He has: virtue, knowledge, self-control, steadfastness, godliness, etc. This is a written picture of our Lord Jesus Christ. Isn't He beautiful?
The Christian is to be earnest in growing up and becoming more like Jesus. He or she is to be purposeful and diligent about it: “make every effort.” Work at learning from Jesus, adding virtue upon virtue and knowledge to knowledge.
And notice the benefits we get as we seek to grow into the image of Jesus:
(8) For if these qualities are yours and are increasing, they keep you from being ineffective or unfruitful in the knowledge of our Lord Jesus Christ.
Yes, growing into Christ-likeness, adding all the virtues listed in this passage keeps us from being ineffective and unfruitful. Sin is what makes us ineffective and unfruitful, as it grieves God’s Spirit and blocks the flow of His power, like a dam on a river. But as we repent and turn to the Lord, as we grasp onto His gospel promises, as we make every effort to grow into Christ-likeness we become effective and fruitful Christians.
But you know what? Every Christian has moments when they stop growing and start drifting. Times when we stop making an effort to conform to the image of Jesus and instead start sliding back into fleshly living. We become self-conscious and discouraged, we lose effectiveness and fruitfulness, and we begin to resemble the first Adam instead of the Last Adam (Jesus Christ). If this continues for any length of time, we can become enslaved to habitual sin again, trapped in lies and a world of deception, weakened spiritually to the point of exasperation.
We become “nearsighted,” having closed our eyes to the truth. We can only see the problems in our lives, the struggles we have, our sin and failures. We have turned inward, become misfocused and misguided, and we will become ineffective in life and unfruitful in ministry. We become nearsighted, no longer seeing the dying world around us or caring about others in need. We become nearsighted and cannot find our way forward.
What happened? What went wrong? Can we ever get back to a life of effective living and fruitful ministry? Oh my yes! Notice what Peter says next:
2 Peter 1:9 ESV For whoever lacks these qualities is so nearsighted that he is blind, having forgotten that he was cleansed from his former sins.