Paul’s gospel is not an extension of the words of Jesus of Nazareth to Israel. The message of Jesus of Nazareth, and that of Paul, are for two different peoples, Jesus to the Jew and Paul to the Gentile, requiring two different gospels, and with different ultimate outcomes. While Paul’s gospel is based upon the same person of Jesus who healed the sick, raised the dead, cast out devils, and performed miracles; Paul’s gospel is an entirely new gospel, differing from that of any previous dispensation. Paul’s gospel does not consist of anything Jesus of Nazareth taught the Jews or did. However, the same Jesus of Nazareth who died and rose from the dead is at the core of Paul’s “mystery” gospel. It is by His shed blood, death, and resurrection as the "spirit of life in Christ Jesus" that Jesus now may live in believers who receive Him. Believers then are the members of the grace dispensation’s “church, body of Christ.”

Paul also wrote these words, acknowledging the correct differentiation between the gospels that Peter and the twelve preached to Israel, and that which Paul preached to the Gentiles. Galatians 2:7-8 But contrariwise (on the contrary), when they saw that the gospel of the uncircumcision was committed unto me (Paul), as the gospel of the circumcision was unto Peter; ⁸ (For he that wrought effectually in Peter to the apostleship of the circumcision, the same was mighty in me (Paul) toward the Gentiles:) Thus, Peter’s gospel was unto Israel “the circumcision” and Paul’s gospel was unto “the uncircumcision (Gentiles)”

From the foregoing we can see that the confusion over God’s “last gospel” given to the Apostle Paul exists only because of the denial, by many within Christendom, of the Apostle Paul’s unique ministry of “the mystery” gospel message to the body of Christ, which he called “my gospel” three times. E.g., Romans 16:25 Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began, 

Whereas, from the beginning God worked toward relationship with all mankind, even after the fall; He ultimately set the Gentiles aside. At that time the Lord God called Abram, desiring to ultimately bless the world through Abram’s family – the nation Israel. Genesis 18:17-18 And the LORD said, Shall I hide from Abraham that thing which I do; ¹⁸ Seeing that Abraham shall surely become a great and mighty nation, and all the nations of the earth shall be blessed in him?

Though Israel was called in Abraham, it was with the stoning of Stephen, a man “full of the Holy Ghost” and whose face had shown with the fullness of “the Spirit,” that the nation of Israel rejected God and…Israel was also “set aside.” This followed Israel’s long rejection of God by their rejection of His prophets, and then their killing of the Son of God. Thus, the Triune God, as the Father, Son, and Spirit, has been fully rejected by Israel. With that, Abraham’s seed did not fulfill God’s call for the children of Abraham to bless the whole world, including the Gentiles. Israel was then “set aside” and God turned “to the Gentiles” (Acts 28:28), who Paul says "will hear it." With the stoning of Stephen in Acts 7, God set Israel aside as He had set aside the Gentiles in Genesis 9, when He called and separated Abram. In these “two settings aside” we see what Paul means when he concludes that “there is none righteous, no not one” – meaning both Jew and Gentile have been set aside. Romans 3:23 For all have sinned, and come short of the glory of God;

Paul explains that we today are blessed not by Israel’s obedience, but “rather through their fall.” Rom 11:11 … but rather through their (Israel’s) fall, salvation is come unto the Gentiles… When Israel rejected the Holy Spirit by stoning Stephen to death in Acts 7, Israel was set aside “until the times of the Gentiles be fulfilled.” Rom 11:25b … blindness in part is happened to Israel, until the fulness of the Gentiles be come in.

With Israel’s fall, Christ from heaven then revealed a totally new dispensation by calling, saving, and appearing to an enemy of the cross, “Saul of Tarsus.” With Israel set aside, Christ gave Saul (now Paul) a new gospel that extends principally to the Gentiles. With this final gospel, there is neither Jew nor Gentile since all are one in Christ (Gal 3:28). Christ, as "the Sprit of life" comes to indwell the human spirit of all to those who receive this gospel that Paul was given by the ascended Christ; they stand "holy and blameless" before God (Eph 1:3-4), “by grace through faith… not of works” of the law (Eph 2:8-9). 

Paul is the last God-appointed Apostle. Paul’s words alone set the pattern for today’s believers. “Follow me as (in the way) I follow Christ" (I Cor. 11:1). We must follow Christ in the way of Paul in order to know Christ in His fullness. Paul, writes “God gave the gospel to me to give to you” (Eph. 3:17, Col. 1:25, I Cor. 9:16-17).