Paul preached Christ’s death for all men. In I Tim. 2:4-7, he states emphatically that this glorious truth was first committed specifically to him:
“Who will have ALL MEN to be saved, and to come unto the knowledge of the truth. For there is one God, and one mediator BETWEEN GOD AND MEN, the man Christ Jesus; Who gave Himself A RANSOM FOR ALL, to be testified in due time. WHEREUNTO I AM ORDAINED A PREACHER, AND AN APOSTLE, (I SPEAK THE TRUTH IN CHRIST, AND LIE NOT;) A TEACHER OF THE GENTILES IN FAITH AND VERITY.”
Note the words “to be,” “in due time” and “whereunto I am appointed.” Thus this glorious message of Christ’s death for all was not part of prophecy or of the so-called “Great Commission,” but was later committed to Paul.
Nowhere in Old Testament prophecy do we read that Christ would die for all, including the Gentiles. Even in that famous prophecy, Isaiah 53, which Gentile believers are so apt to apply to themselves, the Hebrew prophet says: “All we like sheep have gone astray ,” and “the Lord hath laid on Him the iniquity of us all” (Isa. 53:6). Now, if I tell you that “we all,” or “all of us” are going on an outing, this does not mean that all the world is invited. And in this case Isaiah’s meaning is especially clear and emphatic for, speaking still as a Hebrew prophet, he goes on to say: “For the transgression of my people was He stricken” (Isa. 53:8). How then could Paul have meant in I Cor. 15:3 that his preaching of the cross as good news for all, was in fulfillment of prophecy? Indeed, he distinctly states that it was a “mystery,” a secret, first revealed to him.
“For this cause I Paul, the prisoner of Jesus Christ for you Gentiles, If ye have heard of the dispensation of the grace of God which is given me to you-ward: How that by revelation he made known unto me the mystery…” (Eph. 3:1-3). source