What does Ephesians 3:13 mean?

Because of their reasons for great confidence, Paul suggests his readers should not be discouraged to hear of his struggles. Paul also spoke of not losing heart in 2 Corinthians 4:1, stating, "Therefore, having this ministry by the mercy of God, we do not lose heart" (see also 2 Corinthians 4:16). Paul again acknowledges his ministry is because of God, not his own human accomplishments. By the end of his life, Paul still considered himself the chief of sinners (1 Timothy 1:15), though God had used him greatly to impact many lives.

Paul also calls his suffering something which is their "glory." He uses "glory" six times in this letter, yet only here does he mention something intended for the church's glory, rather than for God's. The idea seems to be that Paul suffered on their behalf, and did so honorably. He was not arrested for lawless activities, or immorality, but rather for his faith in Jesus Christ. As a result, many had come to faith and spoke out more boldly for the Lord (Philippians 1:12–18). They could be encouraged at how God continued to work in Paul's ministry, despite all Paul was facing at the time.