16 to reveal His Son in me so that I might preach Him among the Gentiles, I did not rush to consult with flesh and blood, -Galatians 1:16 BSB
The phrase “to reveal His Son in me” refers to Paul being used by the Holy Spirit, after conversion, to tell people about Jesus Christ and what He did for everyone on the cross.
The phrase “I might preach Him among the Gentiles” indicates the direction of Paul’s ministry that God wanted it to go, which wasn’t only for the Jews to know about Jesus but for the whole world—the Gentile nations. We can see the Holy Spirit’s fruit through Paul’s ministry in Revelation Chapters 2 & 3 with the seven churches (Ephesus, Smyrna, Pergamum, Thyatira, Sardis, Philadelphia, and Laodicea) of Asia Minor, in which Jesus tells John to send the Book of Revelation to, see Revelation 1:9-11.
The phrase “I did not rush to consult with flesh and blood” means that Paul received divine revelation through the Spirit of God and who also helped him understand Old Testament prophecies concerning the person and ministry of the Lord Jesus Christ.