For this reason I, Paul, the prisoner of Christ Jesus for the sake of you Gentiles— if indeed you have heard of the stewardship of God’s grace which was given to me for you; that by revelation there was made known to me the mystery, as I wrote before in brief.
By referring to this, when you read you can understand my insight into the mystery of Christ, which in other generations was not made known to the sons of men, as it has now been revealed to His holy apostles and prophets in the Spirit; to be specific, that the Gentiles are fellow heirs and fellow members of the body, and fellow partakers of the promise in Christ Jesus through the gospel, of which I was made a minister, according to the gift of God’s grace which was given to me according to the working of His power. To me, the very least of all saints, this grace was given, to preach to the Gentiles the unfathomable riches of Christ, and to bring to light what is the administration of the mystery which for ages has been hidden in God who created all things; so that the manifold wisdom of God might now be made known through the church to the rulers and the authorities in the heavenly places. This was in accordance with the eternal purpose which He carried out in Christ Jesus our Lord, in whom we have boldness and confident access through faith in Him.
Therefore I ask you not to lose heart at my tribulations on your behalf, for they are your glory.
New American Standard Bible, 1995 Edition
St. Paul knew the people he was writing to; the people of the Ephesian church were worried about his imprisonment. Paul tells believers not to become dishearted (literally, “don’t lose your hearts”) because he is suffering.
St. Paul also plays a strong gambit that isn’t popular in the world today, namely, that everything, peasants, rulers, kings, Caesars, angels, and demons look to the Church to better understand the gospel. He also worked with the most dysfunctional churches of his day and still says the church is indispensable to the work of God.
Jesus Christ and the church were always the plan.