Chapter 3 can be divided into two parts:
3:1–13 - Paul as preacher of Christ’s mystery among the Gentiles;
1.2. 3:1–3 - introduction;
1.3. 3:4–6 - the mystery of Christ revealed;
1.4. 3:7–10 - the significance of Paul’s mission;
1.5. 3:11–13 - God’s eternal purpose;
3:14–21 - Prayer of the apostle for the Ephesians;
2.1. 3:14–15 - introduction;
2.2. 3:16–19 - petitions;
2.3. 3:20–21 - doxology.
3:1–3
The apostle presents himself as “the prisoner of Christ”. In other letters, we have the phrase “slave/servant of Christ” (Rom 1:1; Gal 1:10); Then, we also have the phrase “apostle of Christ” (1 Cor 1:1). It seems that this introductory phrase depends on how the author wants to perceived by the community he writes the letter to. In Romans as the servant - planning to serve the community he does not personally know. In Corinthians as the apostle - because apparently the community was challenging his apostleship credentials. In Galatians both as apostle (Gal 1:1) and servant (1:10).
The reason Paul has become “the prisoner of Christ” are the Gentiles - Ephesians themselves. Moreover, even the grace that Paul has received from God - the grace of preaching the Gospel - was for the sake of the Gentiles - Ephesians.
The grace means the revelation of the mystery of Christ that was given to Paul and the Ephesians have just heard about it (Eph 1:9; 2:14–18). The Greek word “mysterion” - mystery was rendered into Latin as “sacramentum” - sacrament (in Latin version of Saint Jerome - Vulgate - we have here “sacramentum”). That has a powerful significance - Christ as the sacrament of the Father.
3:4–6
The mystery of Christ (mysterio in Latin here - Vulgate) was not revealed before to “the sons of men” - people. It was not known by the Gentile philosophers or poets. It was only revealed with the proclamation of the Gospel. Notice the role of the Spirit in here. The apostles and prophets refers to those who in the Church perform the ministry of proclaiming, preaching and teaching the Gospel.
The content of this mystery was already explained with details in chapter 2 (2:11–13). Here, it is repeated with three adjectives:
All this three “joints” refers to the participation of the Gentiles in all the promises of God that were before directed to the Jews.
The participation takes place through the Gospel - proclamation of the Gospel that leads through faith and baptism to a new status of the Gentiles “in Christ”.
Remember that “justification” means the move from the old Adam - as children of disobedience - to the new Adam, Jesus Christ, our Savior - as the children of God by adoption (the grace of adoption).
3:7–10
The apostle repeats again that his apostleship is God’s grace, his success is due to the power of God, and he himself is a minister of the Gospel
We sense the echo of a great surprise, that Paul was given such a great grace (see Acts 9:15), he “the leaster - apostle coins here a word that would describe how he considers himself among all the faithful - among the saints - all the faithful.
The task of the apostle:
3:11–13
What does the principalities and powers learn through the Church? That the believers can approach the Almighty God with confidence. Imagine. They cannot, but we can. They have to cover their faces when they serve God (Is 6:2), but we through Christ can approach God with boldness.
This eternal purpose - the purpose of ages - was planed and fulfilled in Christ.
Finally, the apostle points to his own cross that is associated with the proclamation of this mystery. As the Cross of Christ became our glory, so our the tribulation of the apostle. Such perception of the suffering is also a kind of grace. In front of tribulations - either ours or our brothers and sisters - we faint, we get discouraged. Paul tries to change our perspective on this point. Here we can call to mind Christ’s saying from Mk 9:34–35.
3:14–15
Verse 3:1 can be connected with 3:14 through the phrase “for this cause” - the same Greek phrase at the beginning. Thus, the prisoner of Christ bows his knees unto the Father.
“Patera” - Father and “patria” - fatherhood. There is play on words here. The Father is the source of all fatherhood “in heaven and on earth”. The same phrase is found in Matt 6:10.
3:16–19
Here we have requests directed to the Father
3:20–21
God is seen as above all our imagination. Even our requests and thoughts pale in comparison to what He can do for us. Here, we can see the rule: the measure of our requests is the measure of our faith.
The object of this powerful statement is God, the Father. The power working in us refers to the Holy Spirit. His glory dwells in the Church and in Christ - like before it dwelled among the people of Israel (see Ex 40:34).
This last request embraces all people of all times, who will be in Christ and in Church. God’s glory always rests on His adopted children and our lives should give glory to Him.