In these verses, and those that follow, Paul addresses the primary heresy threatening the church in Colosse: Gnosticism that denied the deity of Christ. Paul makes it clear and uncomplicated. All the fullness of God dwells in Christ. He was/is the Son of God in human form. His humanity did not/does not diminish in any way his headship and authority over all creation.
Furthermore, the union of every believer with Christ is absolutely complete. In Christ my reconciliation with God is fully complete, my sins are forgiven and my future is eternally secure. God of Heaven’s Armies, the duty sentry has no greater assurance than that in which he/she has put their trust, that is in Christ Jesus our Lord.
Paul must have felt tremendous responsibility for the church in Colosse and Laodicea. He did not found these two churches. Others who had come to Christ through Paul’s ministry (Acts 19:10) found these churches (Epaphras in Colosse – v7). Paul may have thought, “I hope I have adequately discipled these converts and that they may stand strong in the face of adversity and false teaching.”
Paul agonizes for their steadfastness in faith. He encourages them and reminds them of the truth they believed in Christ. He does all he can to continue pointing them to that truth. Lord, I have felt the responsibility of mentoring others in ministry. I have agonized over ministry plants in places near and far. To train and disciple is a joy. It is also a weighty responsibility. Father, may I always take such work seriously.