When one becomes a child of God, he is born again spiritually (John 3:1-5) becoming a spiritual babe who is to grow (1 Pet. 2:1-2; 2 Pet. 3:18). One grows spiritually by feeding upon the word of God (Acts 20:32), developing a spiritual appetite in order to hunger and thirst after righteousness (Matt. 5:6).
2 Peter 1:5-11 tells of the necessity and nature of such growth. "But also for this very reason, giving all diligence, add to your faith virtue, to virtue knowledge, to knowledge self-control, to self-control perseverance, to perseverance godliness, to godliness brotherly kindness, and to brotherly kindness love. For if these things are yours and abound, you will be neither barren nor unfruitful in the knowledge of our Lord Jesus Christ. For he who lacks these things is shortsighted, even to blindness, and has forgotten that he was cleansed from his old sins. Therefore, brethren, be even more diligent to make your call and election sure, for if you do these things you will never stumble; for so an entrance will be supplied to you abundantly into the everlasting kingdom of our Lord and Savior Jesus Christ."
"Virtue" is the determination to do right. "Knowledge" is knowledge of God's word because it is the only source which tells what is right. "Self control" is the application of that knowledge in your life using it to govern your thoughts and actions. "Perseverance" is remaining steadfast to the Lord and His cause. "Godliness" is being like God, as He would have you to be. "Brotherly kindness" is tender affection toward brethren in Christ. "Love" is devotion to God, Christ, and your fellowman which is expressed in obedience to God and service to man.
If you are to be fruitful in your service to Christ, these things must abound in your life. If you lack them, you are blind as to what your life in Christ should be.