Matthew Poole and continuators on Romans 15:21

21. But, as it is written, To whom he was not spoken of, they shall see: and they that have not heard, shall understand .

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 mans Foundation, to put his sickle into anothers harvest, to derive the Glory to himself, which would be due to others, 2 Cor. 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 the Scripture might be fulfilled, which you have in Isa. 52.15. To whom he was not spoken of, they shall see, &c. See the Notes there.