In Romans, Paul considers four different "laws" or systems of law. We've looked at the law of sin, and the law in the creation from ancient times. Now we look at the other two laws: the covenant with Israel, and the gospel of Christ or new covenant.
The Four Laws in Romans (Part 2)
3 The Law of Moses
If God's law was already in the world from ancient times, why did God single out a special nation and bring in a special law for them? If the just could, and did, live by faith before the Mosaical law came in, why was Mosaic law necessary? Paul makes the following points in his letter to the Romans...
To provide a human ancestry for Christ: God's seed promise to Abraham made it necessary for God to choose and ordain through whom the seed should come. Thus: "In Isaac your seed shall be called"(Rom 9:7) and "Jacob have I loved"(Rom 9:13), and "God's Son born of the seed of David"(Rom 1:3). Christ's human ancestry had to be traced from the establishment of the promise to its fulfillment. Israel served this purpose: "Theirs is the adoption as sons, theirs the divine glory, the covenants, the receiving of the law, the temple worship, and the promises. Theirs are the patriarchs, and from them is traced the human ancestry of Christ who is God over all"(Rom 9:4-5).
To raise the awareness of sin: The law of Moses was so holy, the Israelites sinned against it exceedingly. As the world saw that transgression which culminated in the crucifixion of the seed, the world's sin-awareness and accountability was heightened, and its need of grace became more apparent (Rom 5:20,Rom 3:19-20,Rom 7:7,13). The Jews' failure to keep Mosaic law, spurred the world to pursue Abramic faith through a better law (Rom 9:31-32,Ro 10:1-4,Rom 10:16).
To magnify God's glory and grace: Lest the praise be on the chosen people, instead of the seed (who is God the Son), the law made the people "vessels of wrath" whom God by grace "endured with much patience" not destroying them completely but preserving a remnant. Paul sees God's plan and grace unfolding in all of this. (Rom 9:22 Rom 11:5)."Their transgression means riches for the world... their rejection is reconciliation for the world... a partial hardening has happened to Israel until the fulness of the Gentiles has come in"(Rom 11:12,15,25).
To serve as a testimony of faith: From one point of view, the Mosaic law was hostile. "I was once alive apart from the law, but when the commandment came, sin sprang to life, and I died"(Rom 7:9 cf Col 2:14). Whilst this is generally true of all law from God (Rom 3:23), it is especially true of Mosaic law because of that law's complexity. Considered on its own, the Mosaical law created more problems than it solved. However, there is another viewpoint equally as valid: Considered as a stage in the unfolding of God's plan of salvation, the old law served as a manifest and testimony to the need for faith. These two points of view are contrasted in Romans 3:20-22. Standing alone, God's law cannot justify anyone. But when you stand something else beside it, namely faith in Christ, then God's law serves to manifest God's righteousness (Rom 3:26)). So God's law is never nullified by faith, rather it is upheld as a testimony to faith (Rom 3:31). .
4 The Law of Christ
Finally in the unfolding of God's scheme, Christ came and brought in a new law which Paul variously calls...
Gospel of Christ (Rom 1:16)
Form of doctrine (Rom 6:17)
Law of the Spirit (Rom 8:2)
Word of faith (Rom 10:8)
God’s covenant (Rom 11:27)
Perfect will of God (Rom 12:2)
Revelation of the mystery (Rom. 16:25)
Notice that it is proper to regard the gospel as a law and covenant — Paul so regards it. Here he calls it "the law of the Spirit of life in Christ Jesus"(Rom 8:2) In Galatians he calls it, more simply, "the law of Christ"(Gal 6:2).
The difference between Christ's law and the other laws of God, is that Christ's law provides a remedy for sin through the sacrifice he made on the cross. All have sinned and fall short of the glory of God, but now they can be "justified freely by his grace through the redemption that is in Christ Jesus"(Rom 3:23). This cannot happen without law, any more than it can happen without grace. It happens through the law of Christ, the gospel —"the law of the Spirit of life in Christ Jesus has set you free from the law of sin and death"(Rom 8:1-2).