The Law Was Not the Gospel for Adam Either: Against the Covenant of Works
The real point of the law-gospel antithesis is not “conflict”. It is non-identity. The law is not the gospel. The gospel is not the law. The gospel, however, is about the satisfaction of God’s law for God’s elect. Though law and gospel are not the same thing, they are not opposed because they never claim to have the same function.
Law says what God demands. Gospel says how Christ satisfied that demand for the elect. The law never offered life off probation: only one sin would put Adam and his seed under its curse, and no matter how many acts of obedience to the law, the law could never promise everlasting life.
The antithesis does NOT understand Romans 10:4 in terms of abrogation. The “end of the law” is Christ completing all that the law demanded, so that there is no remainder left for the Spirit enabled Christian to do. The gospel says DONE. The gospel does not say “to be done by the life of Christ in the elect”.
Christians sin, and therefore their “fulfillment of the law” (see for example, Romans 13) cannot ever satisfy the law. But the law will not go unsatisfied.
The law, once satisfied by Christ, now demands the salvation of all the elect, for whom the law was satisfied. God the Father would not be just, and God the Son would not be glorified, if the distribution of the justly earned benefits were now conditioned on the imperfect faith of sinners. Yes, faith is necessary for the elect, but even this faith is a gift earned by the righteousness of God in Christ’s work.
This is how the law/gospel antithesis explains Romans 3:31. The law is not nullified but honored by Christ. The only way that its requirements will ever be fully satisfied in the elect (Romans 8:4) is by the imputation of what Christ earned. “
If the law were the gospel, even saying that there’s law (in the garden and now) would be “legalism”. But God is a legalist against legalism. God has told us that the law is not the gospel and that it never was the gospel. Romans 11:5—“So too at the present time there is a remnant, chosen by grace. But if it is by grace, it is not on the basis of works; otherwise grace would not be grace.”
The legalist identifies law and gospel, and then reduces the demand to including what the Spirit does in the elect. But what God does in us (by grace) must be excluded from the righteousness.
The “covenant of works” theory teaches a ”hypothetical gospel” in which Adam supposedly “could have” earned righteousness for others by keeping the law. One clear way to say that the law is not the gospel is to say that the it was not the gospel for Adam either. But the “covenant of works” is not inherent to the law/gospel antithesis.