Paul operates with a fellowship-driven mentality, as Israel’s history, defined by God’s covenant dealings with them, looms large in his thinking. So as we see him, because of God’s justifying activity, incorporating Gentiles into the stories of Adam and Moses to go along with their being incorporated in the story of Abraham, with each story marking the creation of a covenant people (which is also taking place in the church, through the covenant that is marked by belief in Jesus), a demand is placed upon us to continue to allow these thoughts to resonate as we progress through the chapter.
The boundlessness of the covenant and of the grace of God (with that boundlessness not being undefinable or unobservable, but substantively demonstrated through the inclusion of Gentiles within that covenant) is set forth as Paul writes “But the gracious gift is not like the transgression” (5:15a). Remember, because Adam and Israel (Moses) are in view, “transgression” can be understood on multiple levels. Those multiple transgressions are overcome, however, “For if the many died through the transgression of the one man, how much more did the grace of the one man Jesus Christ multiply to the many!” (5:15b). We can point out that Paul believed Jesus, as Messiah (King/Christ), embodied Israel (it was a common understanding that the King stood in for the people), which allows for the transition from Adam to Jesus, encompassing Moses (who was standing in for Israel in this construct) in the process. Thus, we can see the movement from Adam, through Jesus, to the many---the Gentile nations.
Effectively, the covenant had been provided to all people through Adam, who represents all of humanity. Though this is probably an uncommon way of looking at God’s covenant dealings, and though it seems somewhat counter-intuitive on its surface, we can actually insist that God’s original covenant had been made with the whole of humanity, with Adam representing the whole. That covenant was eventually localized to Abraham and his descendants. This includes a number of nations, as we consider the very basic fact that Abraham had two sons, Ishmael and Isaac, both of which had a number of descendants. The covenant with Israel represents a further localizing, as the descendants of Jacob, one of the numerous grandsons of Abraham, are chosen as God’s covenant people. According to the historical narrative on offer in Scripture, we see an ongoing narrowing of the covenant. What at first looks like an expansion, from Adam, to Abraham’s household, to Israel, is actually an ongoing process of restriction. The intentions always remained the same, however, which was to reflect God’s glory into the world and to gather up the praises of God’s creation and return them back to Him.
With the Assyrian conquest of Israel, and the dispersion of the northern ten tribes of the twelve tribes of Israel and their being scattered to the four winds, Judah remains on the playing field as the carriers of the covenant. This is yet another restriction. As we get closer to the time of Jesus, there is an even further narrowing of covenant participants, with groups within the land of Israel creating lines of demarcation that will determine which members of God’s historical covenant people are actually continuing to participate in God’s covenant. From the record of the Gospels, it is the opinion of Jesus that those who are the primarily self-appointed arbiters of covenant in His day have gone horribly astray, are missing the mark, and are presenting a picture of the covenant and Creator God that was set at quite a distance from the God that revealed Himself through Adam, Abraham, Moses, and the prophets. It is from these people that Jesus seizes the role of arbitrator, taking it upon Himself to demonstrate God’s intentions in regards to His covenant with His creation and His image-bearers, doing much to bear this out with His meal practice.
By doing this, Jesus actually represents the final step in this long-running narrowing process. While this means that the covenant has finally moved from the whole of humanity (Adam) to “one man,” Jesus’ re-shaping of the covenant, and His re-structuring of the covenant around Himself, restarts the process. Jesus is the second Adam (or the last Adam), and God’s covenant is now thrown open “to the many,” to all of humanity, as had been the case with Adam. There is, of course, a major difference, in that “the gift is not like the one who sinned,” Adam, “For judgment, resulting from the one transgression, led to condemnation, but the gracious gift from the many failures,” that line of Adam, Abraham, Jacob, Israel, Judah, and the Pharisees, “led to justification” (5:16).
Summing up this section then, and doing so with the entire scope of covenant and salvation history in mind, Paul writes “For if, by the transgression of the one man, death reigned through the one, how much more will those who receive the abundance of grace and of the gift of righteousness reign in life through the one, Jesus Christ!” (5:17) Jesus marks the transition of the ages. Whereas death reigned because of the covenant transgression of the first Adam, that age has been brought to an end. Life now reigns through the covenant faithfulness of the second Adam. In Him, a new creation has begun. A new humanity has been brought into existence, and this humanity, through the grace of God, shares in the gift of righteousness (they are justified, experiencing God’s covenant faithfulness by participating in the new covenant for the new age) by believing in Jesus and His Gospel.
Paul’s “all peoples” focus, which has seen him sharing the history of Israel with Gentiles and in which the covenant moves outward from Israel to take in the whole of creation and all of its peoples, which has been resonant from the beginning of his communication and stands in contrast to any notion that Gentiles needed to move towards Israel so as to participate in the covenant (by adopting its covenant markers), rings out as he moves to the close of the fifth chapter. He writes “Consequently, just as condemnation for all people came through one transgression, so too through the one righteous act came righteousness for all people” (5:18). Covenant participation is for all people, and it comes through belief in Jesus, graciously and faithfully orchestrated by the Creator God. There is not a limited group of covenant participants. God’s redemptive purposes and plans extend to “all,” which he also refers to as the “many,” as opposed to “the few.” Consequently, and we almost find Paul repeating himself as he explores the angles of his thinking and stresses the significance and scope of God’s cosmic plans and the dramatic re-write (according to then-current thinking) that is taking place in Jesus, we read “For just as through the disobedience of the one man many were made sinners, so also through the obedience of one man many will be made righteous” (5:19).