The central message of this sermon is that spiritual growth and maturity require effort and work on our part, despite the fact that salvation is a gift of God's grace. The teacher emphasizes that simply believing in God or wanting to grow spiritually is not enough; we must be willing to put in the time and energy to study His word, focus our attention, and cultivate a deep desire for knowledge of Him. This process involves internalizing the Word, which means bringing it into the deepest recesses of our heart and being, and it requires us to take responsibility for our own spiritual growth rather than relying solely on external authorities or tools. The takeaway is that spiritual maturity is not something that can be easily obtained or handed to us, but rather it requires a lifelong commitment to effort, study, and devotion to God's Word. This central message advances the belief that salvation is not just about intellectual assent, but about a deep and abiding relationship with God that requires ongoing growth and development throughout our lives.