The “glory of God” in Romans 3:23 is the manifestation of His presence. In the Old Testament, God’s presence was the outward Shekinah glory. In the New Testament, God’s glory was manifested in Christ about whom John could testify, “we beheld his glory, the glory of the only begotten of the Father” (John 1:14). Every sinner has fallen short of being Christ like. He is the standard against which every person must measure himself. Every believer is presently being changed into Christ image (Romans 8:28) and one day will perfectly “be changed into the same image from glory to glory even as by the Spirit of the Lord” (2 Corinthian 3:18).
Conversely, Paul exalted the deity of Christ because it was necessary for the God/man to die and atone for the sins of the world. In Philippians 2:5-8, Paul stated that the preincarnate Christ was in “the form of God,” that is, in essence was God. Christ in his humiliation added to His deity “the form of a servant” which is the essence of man, apart from sin, that He might humble himself and become obedient unto death, even the death of the cross. In Philippians, Paul is using theology to heal the disunity of two members, Euodia and Syntyche, who needed to humble themselves and “agree in the Lord” (4:2).
In Colossians 1:19-20, Paul combined the deity of Christ and his death: “For in him all the fullness of God was pleased to dwell, and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.” Paul was again employing doctrine to combat a church problem. The problem at Colossae was the Colossian Heresy which denied the humanity and the deity of Christ.[1] Paul combines Christ’s deity and humanity in Colossians 2:9 and 14 when he wrote: “For in him the whole fullness of deity dwells bodily” (2:9). The God/man went to the cross and canceled the believing sinner’s debt “that stood against us with its legal demands. This he set aside, nailing it to the cross” (2:14). When the atoning work of the God/man is accepted by faith, God justifies or declares that person righteous. Next, the doctrine of justification defends penal substitution.
[1] Doug Moo explained that Colossian heretics were the group that Paul was confronting in Colossians: “The false teachers denigrated Christ. The assumption, widespread in the literature, that the false teachers were directly questioning the supremacy or sufficiency of Christ, especially in comparison with other spiritual beings, is based on what Paul says positively about Christ. In [Colossians] 2:8–23 alone he asserts that Christ is the one in whom “all the fullness of the Deity lives” (v. 9); that Christ is “the head of every power and authority” (v. 10) and that “in Christ” (or “through the cross”) God has triumphed over these spiritual beings (v. 15)” (Douglas J. Moo, The Letters to the Colossians and to Philemon [Grand Rapids: William B. Eerdmans, 2009], 52).