Romans 15:20-22

20It has always been my ambition to preach the gospel where Christ was not known, so that I would not be building on someone else’s foundation.

21Rather, as it is written: “Those who were not told about him will see, and those who have not heard will understand.” Isaiah 52:15 (see Septuagint)

22This is why I have often been hindered from coming to you.