Adam Clarke on Acts 22:21

I will send thee far hence unto the Gentiles - This was the particular appointment of St. Paul: he was the apostle of the Gentiles; for, though he preached frequently to the Jews, yet to preach the Gospel to the Gentiles, and to write for the conversion and establishment of the Gentile world, were his peculiar destination. Hence we find him and his companions travelling every where; through Judea, Phoenicia, Arabia, Syria, Cilicia, Pisidia, Lycaonia, Pamphylia, Galatia, Phrygia, Macedonia, Greece, Asia, the Isles of the Mediterranean Sea, the Isles of the Aegean Sea, Italy, and some add Spain and even Britain. This was the diocess of this primitive bishop: none of the apostles traveled, none preached, none labored as this man; and, we may add, none was so greatly owned of God. The epistles of Peter, John, James, and Jude, are great and excellent; but, when compared with those of Paul, however glorious they may be, they have no glory comparatively, by reason of that glory which excelleth. Next to Jesus Christ, St. Paul is the glory of the Christian Church. Jesus is the foundation; Paul, the master-builder.