Paul states that Jesus is "all in all". Christians often call this "the all-sufficiency of Christ". We sing a song about Jesus that says, "He is my everything, he is my all". Many doctrines diminish Christ's glory and his sacrifice on the cross. We must be careful never to do that.
4 All the Treasures of Wisdom and Knowledge are Hidden in Christ
Col 2:3
"All wisdom and understanding" (Col 1:9) and "full assurance of understanding in true knowledge" (Col 2:2-3) are available in the gospel of Christ. Christ's word lacks nothing (cf 2Pe 1:3,4).
"We don’t cease praying and making requests for you, that you may be filled with the knowledge of his will in all spiritual wisdom and understanding...gaining all riches of the full assurance of understanding, a true knowledge of the mystery of God, both of the Father and of Christ, in whom all the treasures of wisdom and knowledge are hidden"(Col 1:9, 2:2-3).
5 All Things Are Under the Authority of Christ
Col. 2:10
He is the head of all power and
authority (Col 2:10).
He is the first born over all
creation (Col 1:15,18,1Co 15:20).
He is the head of the church (Col 1:18).
He has the highest place (preeminence) in all things (Col 1:18).
He is seated at the right hand of God (Col 3:1).
6 All Our Sins Are Forgiven Through Christ
Col. 2:13
Paul makes the following promises...
In Him we have redemption through His blood. the forgiveness of sins (Col 1:14).
He has made you alive together with Christ, having. forgiven you all trespasses (Col 2:13).
Our sins alienated us from God but we are reconciled through Christ (Col 1:20-23).
We have our sins forgiven when we are buried with Christ (Col 2:12-13,cf Rom 6).
We have our sins forgiven as long as we continue in the faith and be not moved away (Col 1:23,cf Eph 1:13-14).