Charles Hodge on Ephesians 6:20

V. 20. Ὑπὲρ οὗ, for the sake of which Gospel, πρεσβεύων ἐν ἁλύσει εἰμί, I am an ambassador in bonds. An ambassador is one through whom a sovereign speaks. "We are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ’s stead be ye reconciled with God;" 2 Cor. 5, 20. The apostles, as sent by Christ with authority to speak in his name, and to negotiate with men, proposing the terms of reconciliation and urging their acceptance, were in an eminent sense his ambassadors. As all ministers are sent by Christ and are commissioned by him to propose the terms of salvation, they too are entitled to the same honourable designation. Paul was an ambassador in bonds, and yet he did not lose his courage but preached with as much boldness as ever.

Ἵνα ἐν αὐτῷ παῤῥησιάσωμαι, that therein 1 may speak boldly. This may be taken as depending on ἵνα δοθῇ of ver. 19. The sense would then be, ‘That utterance may be given to me—that I may speak boldly.’ But the preceding ἐν παῥῥησίᾳ γνωρίσαι depends on ἵνα δοθῇ. The two clauses are rather parallel. Paul desired that the Ephesians should pray, ‘That utterance should be given him—that is, that he might preach boldly;’ ὡς δεῖ με λαλῆσαι, as I ought to speak. It becomes the man who is an ambassador of God, to speak with boldness, assured of the truth and importance of the message which he has to deliver. That even Paul should solicit the prayers of Christians that he might be able to preach the Gospel aright, shows the sense he had at once of the difficulty and of the importance of the work.