For I will not dare to speak - If the thing were not as I have stated it, I would not dare to arrogate to myself honors which did not belong to me. But God has made me the apostle of the Gentiles; and the conversion of the Gentiles is the fruit of my ministry, Christ having wrought by me for this purpose.
By word and deed - Αογῳ και εργῳ· These words may refer to the doctrines which he taught and to the miracles which he wrought among them. So they became obedient to the doctrines, on the evidence of the miracles with which they were accompanied.
For I will not dare to speak - I should be restrained; I should be afraid to speak, if the thing were not as I have stated. I should be afraid to set up a claim beyond what is strictly in accordance with the truth.
Which Christ hath not wrought by me - I confine myself “strictly” to what I have done. I do not arrogate to myself what Christ has done by others. I do not exaggerate my own success, or claim what others have accomplished.
To make the Gentiles obedient - To bring them to obey God in the gospel.
By word and deed - By preaching, and by all other means; by miracle, by example, etc. The “deeds,” that is, the “lives” of Christian ministers are often as efficacious in bringing people to Christ as their public ministry.