If you'll follow Paul's testimonies about how he was selected by the LORD as apostle to the Gentiles, you'd see that he refers to time spent in Arabia, some thirteen years or so before beginning the greater part of his work. In that time, back at the true Mt. Sinai (in Arabia) as with Moses and Elijah, Paul received from the LORD Jesus what he was to say. The journey to Jerusalem he refers to was to explain his "gospel" to the Jerusalem-based church, still rooted in temple-based worship and observance of Jewish law. The Damascus Road experience and subsequent time spent in blindness until Ananias prayed over him (as instructed by the LORD) isn't the whole story of Paul's apostleship -- he saw the LORD, then spent years with Him before ministry.