Theologians have historically disagreed concerning the nature and purpose of the “Mosaic” Covenant, which God made with Israel at Mount Sinai. Most Presbyterians follow the Westminster Confession (VII:iii-vi) in describing this covenant as merely one administration of the over-arching “Covenant of Grace.” Others have disagreed, saying that this Covenant is a restatement of the Old Covenant of Works made with Adam before his fall. Is the Sinai Covenant the Covenant of Grace? Is it the Covenant of Works? Both? Neither?
John Owen, in his Commentary on Hebrews, describes the Sinai Covenant as being formally neither the Covenant of Grace nor the Covenant of Works, but a national covenant made with Israel which, while pointing to both the principles of works and grace, was itself confined to material, temporal things.
“This covenant 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 forever, but not by virtue of this covenant as formally such.”
At Sinai, God gave Israel a law. What was its relationship to the Covenant of Works?
“It did, indeed, revive the commanding power and sanction of the first covenant of works; and in that respect, as the apostle speaks, was “the ministry of condemnation,” 2 Cor. 3:9; for “by the deeds of the law can no flesh be justified.”
The Sinai covenant included many instructions regarding sacrifices for sin. What was its relationship to the Covnenant of Grace?
“And on the other hand, it directed also to the promise, which was the instrument of life and salvation to all that did believe.”
But despite these shadows and signs of eternal things, the Sinai covenant cannot be formally called either The Covenant of Works, or the Covenant of Grace. It was its own entity, with its own purpose, given to a special people in a special situation in history.
“But as to what it had of its own, it was confined to 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” (Nehemiah Coxe & John Owen, Covenant Theology: From Adam to Christ, pp. 197-198).
The Sovereign Logos 