Christ is the preeminent One in both God's old creation and God's new creation (Col. 1:15-18).
Colossians 1:18a and 3:10-11 reveal that Christ is the Head of the Body, all the members of the Body, and the One who is in all the members of the Body.
Christ is the life of the believers (Col. 3:4), who is revealed into the believers (Gal. 1:16), who lives in and with the believers (Gal. 2:20), who is formed in the believers (Gal. 4:19), who makes His home in the believers (Eph. 3:17), to the glorious image of whom as the firstborn Son of God the believers as the many sons of God are transformed (2 Cor. 3:18; Rom. 8:29), and whom the believers live and magnify through the bountiful supply of His Spirit (Phil. 1:19-21). There is no comparison between Paul's word and James's word.
Without experiencing such a Christ, how can a believer have the genuine Christian perfection, which is the issue of a life lived not by the natural life of the believer but by such a marvelous Christ who lives in him?
The above portrait of Christ also shows the defect in James's presentation of Christ.