Question: "What is spiritual growth?"
Answer: To “abide” is to live, continue, or remain; so, to abide in Christ is to live in Him or remain in Him. When a person is saved, he or she is described as being “in Christ” (Romans 8:1; 2 Corinthians 5:17), held secure in a permanent relationship (John 10:28-29). Therefore, abiding in Christ is not a special level of Christian experience, available only to a few; rather, it is the position of all true believers. The difference between those abiding in Christ and those not abiding in Christ is the difference between the saved and the unsaved.
Abiding in Christ is taught in 1 John 2:5-6, where it is synonymous with “knowing” Christ (verses 2 and 3). Later in the same chapter, John equates “remaining” in the Father and the Son with having the promise of eternal life (verses 24 and 25).
The phrase “abiding in Christ” pictures an intimate, close relationship, and not just a superficial acquaintance. In John 15:4-7, Jesus tells His disciples that having salvation is essential, using the picture of branches united to a vine. Without that vital union with Christ which salvation provides, there can be no life and no productivity. Elsewhere, the Bible likens this union to that of a head and a body (Colossians 1:18).
There are proofs that one abides in Christ (i.e., proofs that one is truly saved and not just pretending). These proofs include obedience to Christ’s commands (John 15:10; 1 John 3:24); following Jesus’ example (1 John 2:6); living free from habitual sin (1 John 3:6); and the awareness of a divine presence within one’s life (1 John 4:13).