In Colossians 1:24-28 Paul posits the thesis of the letter: the gospel as the revelation of the mystery that is Christ. Below is an illustration of how the passage connects with the rest of the letter.
The gospel that Paul preaches is the mystery hidden in the past but now made known. It is proclaimed that all men may become "mature" teleioV in Christ. By that gospel too Paul rejoices inspite of his sufferings because he undergoes them in union with Christ and His Church.
Paul's Sufferings and Christ's Afflictions
After presenting the glorified Christ as the center of the new creation, Paul refers back to the tribulations of the Church as reflected in his person. Christ continues to suffer in His Body, the Church which continues to labor in history under the shadow of the Cross. Paul, a member of that Body, and one who continues to proclaim the graces of God poured through the sacrifice of the Cross, suffers in union with him.
"I fill up with my sufferings the afflictions of Christ...". The passage in no way means that Christ's sacrifice on the cross is insufficient. The Greek word that is translated here as "afflictions" is qliyiV which in the NT refers to the tribulations of the Church. From the use of usterhmata twn qliyewn tou cristou Paul is implying that Christ must undergo a certain amount of tribulation before the end of it comes. What I am calling "a certain amount of tribulation" is hinted at in the "little while" statements found in John 16:16-19; its end is what Paul calls "the earnest expectation of creatures" (Rom. 8:22). In his sufferings, Paul is contributing to the filling up of that measure of afflictions and is, in a way, actually helping to bring the time of afflictions to an end. Paul hints at his sufferings for the word towards the end of the letter. "Remember my bonds" he writes. He was in prison when the letter was being written; prison is the culmination of all the adversities he has received on account of the gospel he proclaims. A glimpse of these sufferings is mentioned in 1 Cor. 4:11-13
Even unto this hour we both hunger and thirst and are naked and are buffeted and have no fixed abode. And we labour, working with our own hands. We are reviled: and we bless. We are persecuted: and we suffer it. We are blasphemed: and we entreat. We are made as the refuse of this world, the offscouring of all, even until now.
The Mystery
"...to make the word of God fully known...". The word that is the gospel proclaimed by Paul is "the mystery hidden through the ages". Paul identifies this mystery as "Christ in you, the hope of glory." A similar passage is found in Luke
Blessed are the eyes which see what you see! For I tell you that many prophets and kings desired to see what you see, and did not see it, and to hear what you hear, and did not hear it. (Luke 10:23-24)
In this Lucan passage, the disciples are witnesses of something that in the past had been hidden from "prophets and kings" -- Christ himself who has made possible the subjection of demons and the fall of Satan.
Christ is a trove of hidden knowledge: "in (him) are hid all the treasures of wisdom and knowledge" Paul writes (Col. 2:3) Elsewhere Paul writes that the mystery is the reconciliation of all things in Christ:
For he has made known to us in all wisdom and insight the mystery of his will, according to his purpose which he set forth in Christ as a plan for the fulness of time, to unite all things in him, things in heaven and things on earth (Eph. 1:9-10)
The stress given by Paul on the sapiential aspect of God's mystery in this letter to the Colossians may be due to an anti-gnostic polemic. Gnosticism is a way of thinking that claims to be based on a secret knowledge that unlocks the mystery of the universe. This way of thinking gave rise to a mysticism that links this secret knowledge to moral perfection and a kind of union with the ground of existence itself. In a sense, it is similar to Buddhism. What makes it different is that it is only for a privileged few: the mature. Paul puts before the Colossians Christ, both Head and Body, as the center of the universe (Col. 1:15-20) stressing that all knowledge and wisdom is found in Him alone (Col. 2:3). This focus on Wisdom is similar to the Johanine assertion that the Word Incarnate is the Truth, and in Him is the life-giving Light that shines on all men.
Perfect/Mature teleioV in Christ
The "mature" in the Christian sense is the new man which is a product of the Cross. It is an upgrade which the Colossians have received in baptism. In Colossians 3, Paul presents this an idea of an upgrade. The life of the Christian is now hidden in Christ with God (1:3). This has a consequence for the moral life:
seeing that you have put off the old nature with its practices ... put on the new man, which is being renewed in knowledge after the image of its creator. (Col. 3:9-10)
The language of "flesh<-->Spirit" that is used in Galatians 5 is re-expressed using "old man <--> new man" terminology. The "burial <-->rising" (Col. 2:12) allussion to the rite of baptism where the candidates descend into the waters taking off their garments and after, as they ascend from the waters, they put on the garb of the baptized, is hinted at here. The clothes that are shed before the baptismal bath is the "old man"; the "new man" is the garb of the Christian that was "put on" after the bath. These are symbols of a redirection in one's moral life and vision of oneself, the world and God, a vision that is clear because of the knowledge of Christ. The life of the Gentile, characterized by what is "earthly" (Col. 3:5) is not compatible with the new status of the Colossians. Rather they should now have a life more in consonance with Christ in whom they have been incorporated (Col. 3:12-4:6)
