Romans 15:20 - Matthew Poole's English Annotations on the Holy Bible

Ver. 20,21. He gives a reason why he chose to preach the gospel in these places, because Christ had not been named or preached there before; this, he saith, was his ambition, and a thing that he greatly coveted; he was unwilling to build upon another man's foundation, to put his sickle into another's harvest, to derive the glory to himself which would be due to others, 2 Corinthians 10:15,16. Again, another reason why he preached the gospel where Christ had not been named, was this, that so by him, as an apostle of Christ, and in his ministry, that scriptnre might be fulfilled, which you have in Isaiah 52:15, To whom he was not spoken of, they shall see, & c. See Poole on "Isaiah 52:15".