The Differences between the Old and New Covenants

 

The terms "Old Covenant" and "New Covenant" can be taken in two sense: either broadly or strictly.

When the Old Covenant is taken in a broad sense, this denotes the entire history of time from Adam until Christ. When taken strictly, it refers to the Mosaic covenant and the ceremonies, taken apart from the promise of grace and deliverance through the Messiah. 

The New Covenant is also taken in this twofold sense. When taken broadly, the New Covenant refers to the general covenant of grace made throughout redemptive history, both before and after the coming of Christ. When taken strictly, it refers to the covenant of grace as administered after the time of Christ, which shall continue to the end of the world. 

You will see some Reformed theologians (such as Robert Rollock and Lucas Trelcatius) speaking of two covenants as though they were diverse in substance and completely separate (and sometimes use this sort of terminology). However, they took the old and new covenants in the strict sense, referring to their separate administrations, and not in the broad sense (in the way that the credobaptists do). These men are not in conflict with other Reformed divines (such as Calvin, Martyr, and Ursinus) who speak one covenant of grace under diverse administrations (when the term "covenant" is taken in the broader sense). This is an important distinction that helps us preserve unity in our doctrine of covenant. 

The Differences Between the Two Covenants

[1]. As to time - This is an obvious difference and clear to all. The old covenant was before Christ, while the new covenant is after Christ. The old covenant referred to Christ as the one to come in the future, the new covenant takes place after Christ was already manifested (cf. Luke 10:23-24). 

[2]. As to clarity - The promises of the gospel and the essential aspects of the covenant of grace are more clearly set forth in the New Covenant, while the Old Covenant had them under the veil of the types and shadows. "But if the ministration of death, written and engraven in stones, was glorious, so that the children of Israel could not stedfastly behold the face of Moses for the glory of his countenance; which glory was to be done away....But we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory, even as by the Spirit of the Lord." (2 Corinthians 3:7, 18)

[3]. As to easiness - The administration of the covenant of grace under the Old Testament is more burdensome and complex than it is under the New Covenant. Saint Augustine said "Thus the sacraments of the Old Testament, which were celebrated in obedience to the law, were types of Christ who was to come; and when Christ fulfilled them by His advent they were done away, and were done away because they were fulfilled. For Christ came not to destroy, but to fulfill. And now that the righteousness of faith is revealed, and the children of God are called into liberty, and the yoke of bondage which was required for a carnal and stiffnecked people is taken away, other sacraments are instituted, greater in efficacy, more beneficial in their use, easier in performance, and fewer in number." (Reply to Faustus the Manichaean, Book XIX, Chapter 13)

[4]. As to sweetness - In the Old Covenant, the condition of perfect obedience was much more emphasized and urged, not to exclude the promises of the gospel, but to drive people (which is why the law is called a "schoolmaster") to Christ, seeing their need for His righteousness. On the other hand, the burden and yoke of the New Covenant is easier and lighter (Matthew 11:30), since we have the fuller manifestation and power of the Holy Spirit to empower us in the same. 

[5]. As to perfection - The Old Covenant administered the covenant of grace under the types and shadows, and in an obscure way.

[6]. As to freedom. The spirit of bondage (Romans 8:15) prevailed under the Old Covenant. Though it was a covenant of grace and the promises were administered then (albeit, obscurely, as said above), the people under that dispensation nonetheless had the threatenings and terrors of Mount Sinai constantly ringing in their ears, so to speak 

[7]. As to amplitude - The Old Covenant was primarily for the people of Israel (though Gentiles could still enter into that nation, Ex. 12:48; Lev. 19:34). However, the New Covenant takes place when the Gentiles are ingrafted into the people of God (both internally and externally); Acts 10:34-35; Col. 3:11.