Adam’s good works were acceptable to God. He could do them and God would receive them. Our own “good” works, our very best works, require the forgiveness of God and the continual intercession of Jesus Christ due to their impurity. Thus, it is appropriate to describe God’s covenant with Adam as a covenant of works and God’s covenant with us as a covenant of grace in that we need and (if we are ultimately to be saved from God’s wrath) receive God’s grace in that he forgives what is lacking in our works.
It is also true that Israel is a new Adam. We see this in Genesis because three people are told to “be fruitful and multiply”: Adam, Noah, and Jacob (35.11). Indeed, God promises Abraham that He will “multiply” him and make him “fruitful” (Gen 17.2, 6). Israel is God’s new humanity. Just as Adam was God’s son (Luke 3.38) so was Israel (Exodus 4.22). Israel is the Son of Man/Adam (Psalm 80.17) who will be temporarily persecuted by beasts before being vindicated and given authority over them like the first Adam (Daniel 7, especially v. 22; c.f. Revelation 20.4).
However, it is entirely unjustified and implausible to say that (1) Adam was supposed to earn or merit future glory from God according to the terms of God’s covenant with him, or (2) individual Israelites were expected by God’s covenant Law to earn or merit salvation and glory from God.
To take (2) first, we are told quite straightforwardly that Zechariah and Elizabeth “were both righteous in the sight of God, walking blamelessly in all the commandments and requirements of the Lord” (Luke 1.6).
John Calvin writes of Luke 1.6:
those magnificent commendations, which are bestowed on the servants of God, must be taken with some exception. For we ought to consider in what manner God deals with them. It is according to the covenant which he has made with them, the first clause of which is a free reconciliation and daily pardon, by which he forgives their sins. They are accounted righteous and blameless, because their whole life testifies that they are devoted to righteousness, that the fear of God dwells in them, so long as they give a holy example. But as their pious endeavors fall very far short of perfection, they cannot please God without obtaining pardon. The righteousness which is commended in them depends on the gracious forbearance of God, who does not reckon to them their remaining unrighteousness. In this manner we must explain whatever expressions are applied in Scripture to the righteousness of men, so as not to overturn the forgiveness of sins, on which it rests as a house does on its foundation (emphasis added).
To those who insist that Luke 1.6 refers to the imputed righteousness of Christ, Calvin replies:
Those who explain it to mean that Zacharias and Elisabeth were righteous by faith, simply because they freely obtained the favor of God through the Mediator, torture and misapply the words of Luke. With respect to the subject itself, they state a part of the truth, but not the whole. I do own that the righteousness which is ascribed to them ought to be regarded as obtained, not by the merit of works, but by the grace of Christ; and yet, because the Lord has not imputed to them their sins, he has been pleased to bestow on their holy, though imperfect life, the appellation of righteousness. The folly of the Papists is easily refuted. With the righteousness of faith they contrast this righteousness, which is ascribed to Zacharias, which certainly springs from the former, and, therefore, must be subject, inferior, and, to use a common expression, subordinate to it, so that there is no collision between them. The false coloring, too which they give to a single word is pitiful. Ordinances, they tell us, are called commandments of the law, and, therefore, they justify us. As if we asserted that true righteousness is not laid down in the law, or complained that its instruction is in fault for not justifying us, and not rather that it is weak through our flesh, (Romans 8:3.) In the commandments of God, as we have a hundred times acknowledged, life is contained, (Leviticus 18:5; Matthew 19:17;) but this will be of no avail to men, who by nature were altogether opposed to the law, and, now that they are regenerated by the Spirit of God, are still very far from observing it in a perfect manner.
The Law was made for sinners in an administration of the Covenant of Grace, not for sinless beings in a covenant requiring sinless obedience. Sinners could keep it. It was designed for sinners. Those who walked by faith in God kept the law. Thus the Law makes multitudinous provisions for sin, the Psalms sing about how God forgives, and the Proverbs exhort us to forgive one another (e.g. Proverbs 10.12; 17.9).
Indeed, the Law regards Israel not as sinless or potentially sinless people who could earn anything from God, but as sinners (First Kin. 8.46; Second Chronicles 6.36; Proverbs 20.9; Eccl. 7.20) saved by grace (Deuteronomy 7.7; 10.15). The fact that God warns them about the peril of apostasy no more means that they are supposed to earn/merit salvation than does Jesus’ warning to his disciples (John 15.1) or Paul’s warning to the Romans (11.17ff) or to the Colossians (1.21-23) or to the Corinthians (First letter, 10.1ff).
As to (1), Francis Turretin writes:
To be true merit, then, these five conditions are demanded: (1) that the “work be undue”–for no one merits by paying what he owes (Luke 17.10), he only satisfies; (2) that it be ours-for no one can be said to merit from another; (3) that it be absolutely perfect and free from all taint-for where sin is there merit cannot be; (4) that it be equal and proportioned to the reward and pay; otherwise it would be a gift, not merit. (5) that the reward be due to such a work from justice-whence an “undue work” is commonly defined to be one that “makes a reward due in the order of justice.” (Seventeenth Topic, Fifth Question, IV, p. 712).
Two of these four conditions could not have been met by Adam. His good works were all due to God and the reward God promised was much greater than the work itself. I don’t think the fifth condition is met either, that such a reward would be due from justice. If one wants to appeal to God’s keeping his promises as justice, I will not deny it, but only point out that such language is used in the Covenant of Grace as well (Jeremiah 10.24; First John 1.8, 9).
Likewise, Zacharias Ursinus, says much the same thing:
No creature, performing even the best works, can merit anything at the hand of God, or bind him to give anything as though it were due him, and according to the order of divine justice… We deserve our preservation no more than we did our creation. God was not bound to create us; nor is he bound to preserve those whom he has created. But he did, and does, both of his own free will and good pleasure. God receives no benefit from us, nor can we confer anything upon our Creator. Now where there is no benefit, there is no merit; for merit presupposes some benefit received (Commentary on the Heidelberg Catechism, p. 486).
Denying merit to Adam in no way detracts from his demerit. A wife being unfaithful to her loving husband is far more evil than an employee failing to fulfill all his contractual obligations. Adam deserved Hell because of his sin.
The Westminster Confession, written after Ursinus but shortly before Turretin, adds to their testimony. It affirms we can never merit anything from God, not only because of our sinfulness in comparison to God’s holiness, but also because of our finitude in comparison to God’s transcendance:
We cannot by our best works merit pardon of sin, or eternal life at the hand of God, by reason of the great disproportion that is between them and the glory to come; and the infinite distance that is between us and God, whom, by them, we can neither profit, nor satisfy for the debt of our former sins, but when we have done all we can, we have done but our duty, and are unprofitable servants: and because, as they are good, they proceed from his Spirit; and as they are wrought by us, they are defiled, and mixed with so much weakness and imperfection, that they cannot endure the severity of God’s judgment (16.5; emphasis added).
Nor does denying merit to Adam deny it also to Christ, who is not a mere Creature but God himself and who voluntarily did an undue work that he had every right to refuse. Jesus’ merits are not jeopardized in any way.
However, it needs to be pointed out that Jesus’ consciousness was centered on trusting his Father, not earning merits. Otherwise, all the exhortations to endure suffering and follow the example of Jesus would not be exhortations to have faith, but exhortations to earn God’s favor. This is unthinkable. Jesus trusted God to save him and so should we.
Consider Hebrews 11.1-12.3. The author of Hebrews gives his readers a long list of examples of Old Testament people who exercised faith and thus inherited salvation. The culmination of this list of “heroes of the faith” is Jesus himself. Yes, Jesus is unique as the author of Hebrews goes to great lengths to explain. But the uniqueness of Christ’s work in our place and as our representative does not contradict the fact that he is the ultimate example of one who trusted God and thus inherited glory and deliverance from death. The author of Hebrews feels no tension between these two truths.
Likewise, if the intended readers of Hebrews wish to benefit from what Christ did in his life and death and deliverance from death, they must not “shrink back” (10.38, 39), but rather they must, for the joy set before them, endure the “cross,” despising the shame, trusting that they will be seated at the right hand of the throne of God (12.2). They must “consider Him who has endured such hostility by sinners against Himself, so that you may not grow weary and lose heart” (12.3). They must “through faith and patience inherit the promises” (Hebrews 6.12).
None of this can have anything to do with “works righteousness” or “merit.” Adam was not supposed to earn salvation and Jesus only needed to do so to make restitution for Adam’s sin. The author of Hebrews is not exhorting his readers to merit salvation by following Christ’s example. Rather he is telling them that a true trust in Christ will entail that we follow Christ because we are confident that he will bring us into our inheritance.
By faith Noah, being warned by God about things not yet seen, in reverence prepared an ark for the salvation of his household, by which he condemned the world, and became an heir of the righteousness which is according to faith (Hebrews 11.7).
Who would dare claim that the righteousness Noah received was his wages for building the ark?
Adam did not need his sins forgiven as Noah did, but the glory promised him was no less an unearned gift. Adam was disinherited (until and unless God saved him through Jesus Christ) not because he failed to earn anything but because he was an unbeliever. He believed the serpent rather than God and thought his future hope lay in the path of disobedience (Genesis 3).