“I am the vine, you are the branches. He who abides in Me, and I in him, bears much fruit; for without Me you can do nothing…. By this My Father is glorified, that you bear much fruit; so you will be My disciples”John 15 v 5 - 8
It is fascinating that Christ often describes the relationship between himself, God and us as that of intertwined vines. The signs that we remain connected to him are growth (versus withering) and fruitfulness (spiritual fruits - Galatians 5:22). The point in all of this is that growth is not an aspiration, it is the consequence of being connected to Christ.
So many christians assume they have achieved spiritual growth by meeting milestones such as services attended, ordinations, messages preached etc. Actually, all that is needed to grow spiritually is to stay connected to God. The nutrients required for growth flows just by staying connected.
How do we stay connected to Christ? Meditating on His words day and night, living it and letting it transform us into his image (Joshua 1 v 8, Romans 12 v 2).
All we need to know is that spiritual growth is simply a function of the effort we put into staying connected to God.