The Apostle Paul
Ephesians 6:20ESV·traditional attribution

for which I am an ambassador in chains, that I may declare it boldly, as I ought to speak.

John Calvin Reformed @genevareformer

20. As I ought to speak; meaning, that to proclaim the truth of the gospel as it ought to be proclaimed, is a high and rare attainment. Every word here deserves to be carefully weighed. Twice he uses the expression boldly, — “that I may open my mouth boldly,” “that therein I may speak boldly.” Fear hinders us from preaching Christ openly and fearlessly, while...

Matthew Henry Presbyterian @wholebiblehenry

Here, I. He desires their prayers for him, Eph 6:19. Having mentioned supplication for all saints, he puts himself into the number. We must pray for all saints, and particularly for God's faithful ministers. Brethren, pray for us, that the word of the Lord may run and be glorified.

Commenting on Ephesians 6:19-24

John Gill Reformed Baptist @doctorgill

For which I am an ambassador in bonds,.... The character the apostle bore was that of an ambassador; and he was an ambassador from and for Christ, in his room and stead; he represented him, he was sent by him, and entrusted by him with the Gospel; he gave him it, and a commission to preach it, and furnished him with qualifications for it; such...