As all things pertaining to life and piety have been given to us by His divine power, through the knowledge of Him who called us by His glory and excellence. By means of which He has given us precious and very great promises, so that through them you may become partakers of the divine nature, having fled from the corruption that exists in the world because of concupiscence.
Then, spiritual growth includes: (1) growing in the knowledge and understanding of the Word of God, (2) decreasing the frequency and severity of sin, (3) growing in the practice of the qualities of Christ, and (4) Grow in faith and trust in God. Perhaps the best summary of spiritual growth is to be more like Jesus Christ.
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In 1st Corinthians 11: 1, Paul says. "Be imitators of me, as I am of Christ." Jesus Christ is the supreme example of what it truly means to be spiritual.
How is it achieved?
For spiritual growth to occur, you first need to make sure that you have a truly spiritual life through faith in the Lord Jesus Christ.
Learning how to grow spiritually is a lifelong journey, which occurs when you read and apply the Word of God in your life. "All scripture is inspired by God, and useful for teaching, for reproof, for correction, for instruction in righteousness, so that the man of God may be perfect, fully prepared for every good work." For spiritual growth to occur, we must be taught, reproved, corrected, and instructed by the Word of God. Then, we will be fully equipped for every good work. This is the essence of spiritual growth.
What are the results?
The fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faith, meekness, temperance. Against such things there is no law. "If you are becoming more emotional, more joyful, more kind, more controlled, etc., then you can be sure that spiritual growth is truly taking place in your life.
God works in different people in different ways. Some people grow quickly, while others grow slowly, but continuously. Our focus should not be to compare ourselves with others, but to compare ourselves with the Word of God.