James's perfection is somewhat of self-cultivation. He speaks of bridling our tongue (3:1-12). To exercise to bridle your tongue is a kind of self-cultivation. He also teaches that man's wrath does not work out God's righteousness (1:20). To resist your temper is also the cultivation of self. The Lord Jesus in the New Testament teaches us that to follow Him, we have to deny ourselves and bear the cross (Matt. 16:24-25). To follow the Lord you must have your self crossed out. The Christian life is not a life of self-cultivation but of self-denial. Self-denial leaves no ground for self-cultivation. This is quite different from James's teaching.
The factors of which and the means by which the genuine Christian perfection is brought forth and carried out are much more, much greater, higher, richer, stronger, more divine, more spiritual, more heavenly, more organic, more productive, more excellent, more profound, more unfathomable, and more for the union and mingling of the believers with the Triune God than the factors and means for the producing and carrying out of the Christian perfection stressed by James.
Now we want to see the functions of the genuine Christian perfection, or living. The first function is making oneself perfect and maturing oneself in life to live Christ and magnify Christ as the preeminent One, who is revealed in him, who lives in him, who is formed in him, and who is making His home in his heart (1 Thes. 3:13; 1 Pet. 2:2; Col. 1:28; Eph. 4:15; Phil. 1:20-21; Col. 1:18; Gal. 1:16; 2:20; 4:19; Eph. 3:17). Our perfection is for living Christ and magnifying Christ. He is revealed in us, lives in us, is formed in us, and is building His home within us day by day.
The genuine Christian perfection also functions to perfect the members of Christ (Eph. 4:12).
Making the church the fullness of both God and Christ as Their expression is another function of the genuine Christian perfection (Eph. 1:23; 3:19).