When and where was Paul commissioned to go to the Gentiles?

Les explains that Paul was commissioned right away at his conversion at Damascus, when God told Ananias He would send him far hence to the Gentiles. Les points out that everything from Genesis 12 until Paul's epistles was directed primarily, if not exclusively, to the Jew, especially under the law. But this man was commissioned at Damascus to go to the Gentiles. Then God took him out in the desert and gave him His revelations, which Paul refers to in Galatians chapter 1, how by revelation God made known unto him all these things that would come from his pen and not be found elsewhere in the Bible. Les also notes that Paul's pen says all Scripture is inspired of God, all of it profitable, and Paul never lifts himself up as the only one to pay attention to, yet he brings out many doctrines found nowhere else, so we should spend much time in Paul's epistles and funnel back and forth throughout the rest of Scripture.