He is the image of the invisible God, the firstborn over all creation.  (16) For by Him all things were created that are in heaven and that are on earth, visible and invisible, whether thrones or dominions, principalities or powers.  All things were created through Him and for Him.  (17) And He is before all things, and in Him all things consist.  (18) And He is the head of the body, the church, who is the beginning, the firstborn from the dead, that in all things He may have preeminence. (19) For it pleased the Father that in Him all the fullness should dwell, (20) and by Him to reconcile all things to Himself, by Him, whether things on earth or things in heaven, having made peace through the blood of His cross.

The letter to the Colossians was written by the Apostle Paul.  He had been warned about a heresy that was gaining ground in the church at Colosse and our verses today are the heart of Pauls message in response to this heresy.   He is unequivocally rebuking  those who questioned deity of Christ Jesus.

There was an “Angel cult” at Colosse and there was a belief that Angels were emanations from God – and some of the Colossians believed that Jesus was an emanation from God along with them. There was never any doubt in Pauls mind about Christ Jesus.  Everything was at stake over the person of Christ and there is no question that Paul here is placing Christ as divine. The issue was/is clear:  the divinity of Christ is foundational to Christianity. The Jews rejected Christ and now the heretics deprecated Christ. Pauls answer was that Jesus Christ is fully human and fully divine.  Christ is the exact image of God; the Word of God;  the Son of God. Christ is true God of true God.  Paul was determined that the heresy at Colosse not rob the Christians there of salvation and of their Lord Jesus Christ.