“All the maturity in the Christian life flows from Christ because he is fully God and because he has died for us. Because of this, Paul proclaims only Christ both to the unbeliever and the believer. He never goes beyond Christ. He does not say that the beginning of the Christian life is faith in Christ and accepting his work in thanksgiving, and that fullness in the Christian life comes through a higher experience such as being “baptized in the Spirit.” ….
“Paul insists that Christians have already come to fullness of life simply through faith in Christ. We will continue to grow as we understand and are thankful for Christ’s work. Without gratitude for Christ’s death there will be no change and no possibility of change. Thanksgiving is fundamental.
“Why is thankfulness the basis for change? Because it alone can soften our hearts which are so rebellious toward God and his law… Thankfulness points us away from what we have achieved or failed to achieve and makes us focus instead on God’s love, which alone can warm our cold hearts and set them on fire with delight in God and in serving and obeying him.”
– Jerram Barrs, Being Human