If it is the case that apart from Christ we can do nothing that means that disciples must be taught what it means to abide in Christ and how to abide in Christ. Otherwise, all the disciplines and rituals of Christian practice are just for show.
As the branch cannot bear fruit of itself, unless it abides in the vine, neither can you, unless you abide in Me (John 15:4 NKJV).
Paul prods us, “Having begun by the Spirit, are you now being perfected by the flesh?” (Gal. 3:3, ESV). The question is not to elicit an answer but to make a point. The Spirit who gave us life through faith in Jesus Christ is the same Spirit who matures us in Christ. Justification is the handiwork of God’s grace. So is sanctification, our spiritual growth wherein Christ is formed in us.
Just as we cannot give ourselves life, we cannot make ourselves grow. To use the analogy of a child, we can eat the right foods but only in conjunction with God’s design for our maturation will we develop as we should.
Our Lord Jesus brings another metaphor to bear when it comes to our spiritual development. He speaks of a vine and branches. Any of us who have tried to grow vegetables can relate to the image. When my wife and I bought our first home we ambitiously planted a garden. I say ambitiously because we had little idea of the amount of work involved or exactly what we were doing. For example, we planted several zucchini plants, little aware of how prolific they were.
One thing we did know was that if we plucked a growing zucchini off the plant it would no longer grow. Its life was bound up in the plant and its growth depended on its remaining on the plant.
That’s the gist of the metaphor Jesus uses for our spiritual life, growth, health, vitality, and fruitfulness. Life is bound up in Him. We have life only through union with Him. Our spiritual development comes only through remaining connected to Him.