Romans 15:23

but now, having no more any place [territory where Christ is not known] in these regions, and having these many years a longing to come unto you [Because of the many benighted places in the unevangelized east, I have hitherto been held back from visiting you, but now the work here being finished, leaving me free, I find the very principle which once detained me in the east now impels me to seek those of the west, thus permitting me to visit you in passing (comp. Romans 1:11; 1 Thessalonians 3:6; 2 Corinthians 7:7-11; Philippians 1:8), and I purpose to so do. As Rome was a place already founded in Christ, Paul's principle limited his stay there to a mere visit, but as it was the center of all influence in his Gentile field, it was fitting that it rest under his instruction. To compass this instruction Paul wrote this Epistle],