If you were a first century church, you would have been tempted to despair upon hearing the news that Paul was imprisoned: "Was God's purpose being thwarted?!"  In these verses, Paul reassures the Ephesians that this is not the case.  He, who had formerly made the Church suffer, was called to suffer for the benefit of the Church.  In His wisdom, God was continuing to use suffering to display His glory.  Christ accomplished salvation through suffering.  Now, God was applying salvation through Paul's suffering.  A suffering Savior?  A suffering messenger?  It looks foolish to the world, but it's not to God, who is using it to create a Church that will worship Him by faith.  We take heart that God continues to use the sufferings of His People to fulfill His plans and rejoice that "the way of the cross" leads to glory.