Believers grow in the grace and knowledge of our Lord Jesus Christ. Those who are born again desire the "sincere milk" of God's word (1 Peter 2:2). This comes through Bible study and teaching. We are enabled by the Holy Spirit to understand more and more of God's truth in Christ. That's how we grow in Christ.
In the New Testament, salvation includes regeneration and sanctification. "He who has begun a good work in you will complete it until the day of Christ Jesus" (Philippians 1:6). Through regeneration believers have been born again in Christ. Sanctification is growing as believers in Christ.
Immediately upon regeneration, sanctification sets us apart in Christ (1 Peter 1:2). Regeneration is an immediate act by the Holy Spirit within our hearts, whereas sanctification is an ongoing work of the Holy Spirit within us. Simply stated, regeneration is our new birth in Christ, whereas sanctification is our growth in Christ.
The Holy Spirit will guide us to grow in the truth of Christ (John 16:13). It is necessary for us to yield to the Spirit, otherwise we become carnal Christians (1 Corinthians 3:1-3). Our choice is between the Spirit and the flesh. It is an ongoing battle in every believer's life (Galatians 5:16-17). Yielding to the flesh hinders our growth in Christ.
