John Owen

Before reading these quotes, I humbly recommend doing what I did. Spend some time reading through Exodus, Leviticus, Numbers, & Deuteronomy. Do so with a set of highlighters. Highlight every curse or blessing that is temporal/physical in green. Highlight every curse or blessing that is eternal in blue. Highlight every conditional statement or command in orange. Then go back and see how much of your bible is blue.

This covenant [Sinai] thus made, with these ends and promises, did never save nor condemn any man eternally. All that lived under the administration of it did attain eternal life, or perished for ever, but not by virtue of this covenant as formally such. It did, indeed, revive the commanding power and sanction of the first covenant of works; and therein, as the apostle speaks, was “the ministry of condemnation,” 2 Cor. iii. 9; for “by the deeds of the law can no flesh be justified.” And on the other hand, it directed also unto the promise, which was the instrument of life and salvation unto all that did believe. But as unto what it had of its own, it was confined unto things temporal. Believers were saved under it, but not by virtue of it. Sinners perished eternally under it, but by the curse of the original law of works. (Owen, Works, XXII:85-86)

“wherefore we must grant two distinct covenants, rather than a twofold administration of the same covenant merely, to be intended” (XXII, p.76).

Owen on the Mosaic Covenant (pilgrim people)

Herman Witsius

1. Not Formally the Covenant of Works: “1st. Because that cannot be renewed with the sinner, in such a sense as to say, if , for the future, thou shalt perfectly perform every instance of obedience, thou shalt be justified by that, according to the covenant of works. For, by this, the pardon of the former sins would be presupposed, which the covenant of works excludes. 2dly. Because God did not require perfect obedience from Israel, as a condition of this covenant, as a cause of claiming the reward; but sincere obedience, as an evidence of reverence and gratitude. 3dly. Because it did not conclude Israel under the curse, in the sense peculiar to the covenant of works, where all hope of pardon was cut off, if they sinned but in the least instance.”
2. Nor Formally the Covenant of Grace: “Because that requires not only obedience, but also promises, and bestows strength to obey. For, thus the covenant of grace is made known, Jer. xxxii. 39. ‘and I will give them one heart, and one way, that they may fear me for ever.’ But such a promise appears not in the covenant made at mount Sinai. Nay; God, on this very account, distinguishes the new covenant of grace from the Sinaitic, Jer. xxxi. 31-33. And Moses loudly proclaims, Deut xxix. 4. ‘yet the Lord hath not given you a heart to perceive, and eyes to see, and ears to hear, unto this day.’ Certainly, the chosen from among Israel had obtained this. Yet not in virtue of this covenant, which stipulated obedience, but gave no power for it: but in virtue of the covenant of grace, which also belonged to them.”
3. A National Covenant Between God and Israel: “…whereby Israel promised to God a sincere obedience to all his precepts, especially to the ten words; God, on the other hand, promised to Israel, that such an observance would be acceptable to him, nor want its reward, both in this life, and in that which is to come, both as to soul and body. This reciprocal promise supposed a covenant of grace. For, without the assistance of the covenant of grace, man cannot sincerely promise that observance; and yet that an imperfect observance should be acceptable to God is wholly owing to the covenant of grace. It also supposed the doctrine of the covenant of works, the terror of which being increased by those tremendous signs that attended it, they ought to have been excited to embrace the covenant of God. This agreement therefore is a consequent both of the covenant of grace and of works; but was formally neither the one nor the other.”

Witsius on the Mosaic Covenant (reformed blogging)

James Buchanan

“The addition of the Law was not intended to alter either the ground, or the method, of a sinner’s justification, by substituting obedience to the Law for faith in the Promise; … Believers were justified, therefore, under the Law, not by works, but by faith: by faith, they were ‘the children of Abraham,’ and ‘heirs with him of the same promise.’ The Law–considered as a national covenant, by which their continued possession of the land of Canaan, and of all their privileges under the Theocracy, was left to depend on their external obedience to it,–might be called a national Covenant of Works, since their temporal welfare was suspended on the condition of their continued adherence to it; but, in that aspect of it, it had no relation to the spiritual salvation of individuals, otherwise than as this might be affected by their retaining, or forfeiting, their outward privileges and means of grace” (James Buchanan, The Doctrine of Justification, pp. 38-39).
The Doctrine of Justification (Google Books)

Meredith Kline

“…the old covenant order was composed of two strata and the works principle enunciated in Leviticus 18:5, and elsewhere in the law, applied only to one of these, a secondary stratum. There was a foundational stratum having to do with the personal attainment of the eternal kingdom of salvation and this underlying stratum, continuous with all preceding and succeeding administrations of the Lord’s Covenant of Grace with the church, was informed by the principle of grace (cf., e.g., Rom 4:16). Because the Abrahamic covenant of promise found continuity in the Mosaic order at this underlying level, it was not abrogated by the latter. The works principle in the Mosaic order was confined to the typological sphere of the provisional earthly kingdom which was superimposed as a secondary overlay on the foundational stratum… The Israelite people corporately could maintain their continuing tenure as the theocratic kingdom in the promised land only as they maintined the appropriate measure of national fidelity to their heavenly King.”

Quoted in “Works in the Mosaic Covenant” Lee Irons
http://www.upper-register.com/papers/works_in_mosaic_cov.pdf

Michael Horton

“Many critics of federal theology misunderstand the tradition to be saying that the entire theocratic period as a works arrangement (i.e., that Old Testament believers were justified by their personal obedience). But this fails to recognize the nuances in classic covenant theology at this point; namely, that national Israel, with Moses as its mediator, is not the equivalent to the covenant of grace, with Christ as its mediator in both testaments. The two exist side by side throughout the theocratic era, one operating as a typological earthly kingdom on a works principle; the other operating as a spiritual kingdom on the grace principle. Meredeth Kline is a masterful exegete, but he is hardly the first to articulate these views.

As Paul makes clear in Galatians (especially chapter 3), there was the heavenly Zion and its way of salvation (grace alone through faith alone) and a typological earthly Zion and its way of national preservation (conditioned upon her obedience). The inheritance of the typological land was based on law, while the heavenly rest was based on promise, Paul insists. It is not an either/or here, but two distinct operations: the typological land promises indicating in a shadowy, figurative way what was to come when the true Israel would come and perfectly fulfill God’s commands and the spiritual promises in which individual Israelites rested just as we do today (Heb. 4:1-5).”

http://spindleworks.com/library/CR/horton.htm

R. Scott Clark

“Israel was under a typological, not soteriological covenant of works. It’s a post-lapsarian, typological covenant of works.”

-on the Puritanboard: Horton, the Mosaic Covenant, and the WCF