Why did God set Paul apart from his mother's womb and call him by grace?

Les explains that Paul did not receive the gospel from man, nor was he taught it by man, but by revelation of the Lord Jesus Christ. During Paul's revelations, Jesus Christ was in glory. Everything Paul writes concerning doctrine today comes from the ascended Lord, after His death, burial, and resurrection. Until Jesus went to the cross and died, He was not the object of faith to the main run of Gentiles. Once He finished the work of the cross and revealed His plan of salvation to Paul, it became that gospel Paul preached to the Gentiles. In verse 15, it pleased God, who separated Paul from his mother's womb and called him by His grace, to reveal that God could give this man the revelation of Jesus the Son, and that Paul might preach Him among the Gentiles. Paul then did not confer with flesh and blood or go up to Jerusalem.