When I adhered to the Mid Acts position of dispensational theology, I was taught and believed that when Paul was converted and commissioned on the road to Damascus, he was given a new gospel – a gospel of grace to offer to Jew and Gentile alike, as opposed to the "kingdom gospel" which required not only faith in the Messiah Jesus Christ but also obedience to the works of the Law as a demonstration of that faith. This kingdom gospel of faith + works would gradually diminish away when the members of the kingdom church passed off the scene, but would return when Israel's program comes back into play following the culmination of the dispensation of grace.
I must admit that I always felt a little sorry for the kingdom believers that they weren't offered the pure grace that we in this grace age enjoy. It was explained to me that Israel was under a series of curses (Leviticus 26) and thus had something to prove to God in order to gain a right to dwell in the earthly kingdom. It troubled me that the Scriptures make it clear that the Lord Jesus Christ died as a "ransom," so why did Israel need to add to that? I know the gospels say, "ransom for many" (Matthew 20:28; Mark 10:45), and only Paul declares him a "ransom for all" (1 Timothy 2:6), but a ransom is a ransom.
Paul's gospel of grace through faith in Christ alone and not by works was not something new but actually something very, very old! It was the basis by which God desired men to come to him since the beginning of time! If Adam and Eve had trusted God completely, they would not have allowed the serpent to tempt them away from him. Cain would have brought the blood sacrifice God desired and not been convinced his own way was better. The Israelites would have gone immediately into their promised land if they had trusted God to be their all in all.
Paul uses the example of Abraham when he describes this faith God is seeking and mentions King David who described the "blessedness of the man, unto whom God imputeth righteousness without works." (Romans 4) God gave Israel the entire Acts period to turn from their rebellion to faith in his Son, Jesus Christ, who gave his life's blood as their ultimate Passover for their redemption. Some will object that James insists that Abraham was "justified by works" (James 2:17-26). This justification has to do with being approved of God by works of righteousness after being justified and declared righteous by faith. Abraham had been justified by faith long before his willingness to sacrifice his son, Isaac. (Genesis 15:5-6)
Paul quotes from the Old Testament prophet Habbakuk, "the just shall live by faith." (Romans 1:7; Galatians 3:11; Hebrews 10:38). He does this to convince his hearers that grace by faith was God's plan all along for all believers! Romans 16 ends with, "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, But now is made manifest, and by the scriptures of the prophets [like Habbakuk?], according to the commandment of the everlasting God, made known to all nations for the obedience of faith; To God only wise, be glory through Jesus Christ for ever. Amen." 1 Corinthians 2:6-8 speaks of this mystery, this glorious secret kept from the princes of this world, for had they known Christ's sacrifice and subsequent resurrection from the dead would make salvation possible for all men, they would "not have crucified the Lord of glory." This mystery was "kept secret since the world began," not since before the world began like the mystery of our new hope and calling of Ephesians 3, which "hath been hid from ages and generations," and was revealed to Paul only after Israel's official rejection of their kingdom in Acts 28:23-28. (2 Timothy 1:9; Titus 1:2)
Peter, in Acts 15:11, simply states, regarding the inclusion of Gentiles into the kingdom hope of Israel, "But we believe that through the grace of the Lord Jesus Christ we shall be saved, even as they." The kingdom church was still "all zealous of the law" as late as Acts 21:20. Is that grace? It is if by grace through faith they were saved even as the Gentiles invited in were saved. The law was observed by these Jewish kingdom saints because by their obedience, they would be rewarded in the kingdom they received through God's grace.
Paul's gospel during the Acts period was adjusted slightly for the Gentiles that believed so they would not be burdened by Jewish law and rituals, although they were instructed to observe four "necessary things." (Acts 15:28-29)
Today, in this dispensation of the creation of the one new man, Jew and Gentile in the same body, destined for heavenly places, revealed following Acts 28, our works will be rewarded with crowns and positions of authority in those heavenly places, and all laws and ordinances are nailed "to his cross." (Colossians 2:13-14)
God desires "all men to be saved, and to come unto the knowledge of the truth." (1 Timothy 2:4) This was his desire from the beginning when he made man in his image, that man would have fellowship with him. Sin necessitated that he send his Son to die for sin in our place so that all who trust him will be saved - no conditions attached other than that. Christ's cross work opened the floodgates of God's marvelous grace to be offered to all that love him - past, present, and future. This is God's everlasting gospel!