Staying Focused
Paul turns his attention from who Jesus is, to what Jesus has done and how it affects his readers. Jesus, Paul writes, will be able to present them as "holy and blameless" _provided that_ they continue and not shift from the gospel.
Paul's concern was that the Colossians and, by extension, others would be carried away by regulations and distractions. He wrote Colossians to remind them of the hope and person of Jesus through the Gospel.
Colossians 1:21–23The New Revised Standard Version
And you who were once estranged and hostile in mind, doing evil deeds, he has now reconciled in his fleshly body through death, so as to present you holy and blameless and irreproachable before him— provided that you continue securely established and steadfast in the faith, without shifting from the hope promised by the gospel that you heard, which has been proclaimed to every creature under heaven. I, Paul, became a servant of this gospel.