3.How did Paul learn the hidden aspects of this Divine grace

The Holy Spirit of God taught the Apostle Paul by revelation the mystery of the new covenant.

None of the other Apostles understood as clearly as Paul the nature of the new covenant. To Paul was entrusted the transition from Moses to Christ. To Paul was entrusted the explanation of justification by faith. To Paul was entrusted the mystery of the Body of Christ—the other writers of the New Testament do not use this expression.

If the New Testament consisted only of the four Gospels, Acts, and the writings of Peter, James, John, and Jude (the writings of Paul being absent), the principal explanation of the new covenant would not be available for us to study.

The new covenant was explained to Paul by the Holy Spirit during the season that Paul went away to Arabia, shortly after his experience on the road to Damascus (Galatians 1:17).

It is surprising that God would entrust such important spiritual understanding to one man. The Scriptures teach us that God prefers to use individuals whom He perfects and has communion with rather than committees or organizations.

The sacred secret that Christ revealed to Paul is described in Chapters One and Two of the Book of Ephesians.