Spiritual growth is the change and growth of the spiritual nature of our being. It involves spiritual transformation and growth to maturity and completion.
Spiritual maturity has two key characteristics: discernment and self-control. Discernment is necessary for self-control.
When we are spiritually mature, we will no longer be infants tossed about by deception.
And he gave the apostles, the prophets, the evangelists, the shepherds and teachers, to equip the saints for the work of ministry, for building up the body of Christ, until we all attain to the unity of the faith and of the knowledge of the Son of God, to mature manhood, to the measure of the stature of the fullness of Christ, so that we may no longer be children, tossed to and fro by the waves and carried about by every wind of doctrine, by human cunning, by craftiness in deceitful schemes. (Ephesians 4:11-14).
The mature person has their senses trained to discern both good and evil.
Solid food is for the spiritually mature, the person who by constant use has trained their senses to discern good from evil. (Hebrews 5:14).
So, spiritual growth involves the transformation to a new way of discerning and the maturation of that new way.
A spiritually mature person has self-control.
If anyone does not stumble in what he says, he is a spiritually mature man, able also to bridle his whole body. (James 3:2)
So, spiritual growth also involves the transformation to a new way to control ourselves and the maturation of that new way.
A spiritually mature person has all of the spiritual attributes necessary for life and godliness. Spiritual growth involves the addition and maturation of those attributes.
To grow spiritually we must do two things. We must sever our connection with the flow of corruption that sustains and strengthens our corrupt spiritual nature. We must form a continuous, eternal connection with the flow of incorruptibility that will form, sustain, and strengthen a new spiritual nature in us.