According to Reformed theology, when did the New Covenant start?

Question

When instituting the Lord's Supper, Jesus Christ said (Luke 22:20, NIV):

In the same way, after the supper he took the cup, saying, “This cup is the new covenant in my blood, which is poured out for you.

And in Jeremiah 31 the new covenant is also mentioned, with the blessings of the covenant listed. Hebrews 8 talks about the new covenant superceding the old in some way (the details of which perhaps I will put in another question).

At which stage did this new covenant supersede the older covenant, according to Reformed theology?

Answer 1

Reformed theology's view of the "covenants" of scripture is that they are administrations of a single covenant, a covenant of grace. Thus the "new covenant" that Christ talks about is seen as something that in many ways had existed long prior. As Louis Berkhof writes:

The covenant of grace, as it is revealed in the New Testament, is essentially the same as that which governed the relation of Old Testament believers to God. [...] If it is sometimes spoken of as a new covenant, this is sufficiently explained by the fact that its administration differs in several particulars from that of the Old Testament. (Systematic Theology, 2.3.5.C)

The differences that Berkhof sees in the "new covenant" are its universal nature, its greater emphasis on grace, and its richer blessings. But in essence it is the same covenant as that given to Abraham, Moses, and others. So strictly speaking, while the "new covenant" begins in the New Testament with the life, death, and resurrection of Jesus, it is essentially the same covenant as the "old covenant" that preceded it.

Robert Reymond agrees, and quotes John Murray:

The blessings of the covenant of grace which believers enjoy today under the sanctions of the New Testament economy are founded upon the covenant which God made with Abraham. Said another way, the "new covenant" itself is simply the administrative "extension and unfolding of the Abrahamic covenant." (ST, ch 14)

Reymond refers to Hebrews 8 to argue that the Mosaic tabernacle foreshadows the "true, heavenly Tabernacle into which Christ himself entered with his own blood as the redeemed man's High Priest." Reymond specifically sees the incarnation and crucifixion as foundations of the "new covenant":

Christ's "entrance into the heavenly sanctuary" occurred when he assumed his high priestly role as Mediator of the new covenant at the incarnation, and the Most Holy Place was his cross! (ST, ch 14)

John Frame helpfully explains how this "new covenant" is "time transcending" – how it has beginning in Christ but its efficacy extends into the past:

The new covenant does have a temporal inauguration. Covenants are typically inaugurated by the shedding of blood, and that is certainly the case with the new covenant, by the blood of Christ, the blood that fulfills all the blood of bulls and goats in the other covenants. [...]

Nevertheless, as we saw earlier, the efficacy of the new covenant, unlike that of previous covenants, extends to God's elect before Jesus' atonement. When believers in the OT experienced "circumcision of the heart," or when they were Jews "inwardly," they were partaking of the power of the new covenant. (ST, 80)

So to summarize – Reformed theologians see the "new covenant" as an administration of the more general "covenant of grace," and in essence identical to the covenants laid out in the Old Testament. But while it applies to all of redemptive history, the "new covenant" has its historical inauguration in the life and particularly the death of Christ on the cross.

Answer 2

In this sermon by James Orr, a prominent Presbyterian minister of the 19th century, we have some guidance on this question:

http://biblehub.com/sermons/auth/orr/the_ratification_of_the_covenant.htm

He makes a few points, here quoted:

(1) Moses "builded an altar under the hill, and twelve pillars, according to the twelve tribes of Israel" (ver. 4).

(2) Young men of his appointment sacrificed burnt-offerings and peace-offerings unto the Lord. (ver. 5).

(3) The blood of the sacrificed animals was divided: half was put in basins, and half sprinkled on the altar (ver. 6).

(4) The words of the book of the Covenant were next solemnly read in the audience of the people; and the latter renewed their assent to them (ver. 7).

(5) The blood was then cast upon the people out of the basins, and the Covenant was declared to be concluded (ver. 8). Two points here claim our attention.

1. The ratifying of the Covenant with sacrifice; and

2. The action with the blood.

Both were significant.

The Last Supper speech is the reading of the new covenant. The carrying and erection of the cross is the building of the altar. The crucifixion of Jesus is the sacrifice. The piercing of Jesus with the spear and the flow of blood is the sprinkling of blood on the altar. The final act that is required is that the blood also be sprinkled on the people binding themselves to the covenant. Since Jesus called the wine of the communion table his blood, it follows that when the Apostles and other disciples first took communion after the resurrection, the new covenant was ratified. This may be when Jesus appeared and ate fish with them, or when the two who were on the road to Emmaus broke bread with Jesus. An alternate view is that this happened on the day of Pentecost.

At the very least, we know that the new covenant did not start until after the crucifixion. HEBREWS 9:14-17 NASB

14 how much more will the blood of Christ, who through the eternal Spirit offered Himself without blemish to God, cleanse your conscience from dead works to serve the living God? 15 And for this reason He is the mediator of a new covenant, in order that since a death has taken place for the redemption of the transgressions that were committed under the first covenant, those who have been called may receive the promise of the eternal inheritance. 16 For where a covenant is, there must of necessity be the death of the one who made it. 17 For a covenant is valid only when men are dead, for it is never in force while the one who made it lives.

Answer 3

As to when the New Covenant came into force, the answer is simple:

For where a testament is, there must also of necessity be the death of the testator. For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth. (Hebrews 9:16-17, KJV)

David VanDrunen (Professor of Systematic Theology and Christian Ethics at Westminster Seminary), affirms this, that "the redemptive act of Christ's crucifixion itself established the new covenant." (Divine Covenants and Moral Order: A Biblical Theology of Natural Law, p. 85) Likewise affirms Gill, and others.

This superseded the Old Covenant, In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away. (Hebrews 8:13, KJV)

The vanish refers to the practice, foretelling the destruction of the Temple, among other things, as Gill notes, which included the genealogical records of the priests and other things required under the Law. Thank God.

However, contrary to lawlessness, believers are those who seek to walk not after the flesh, but after the Spirit, as the Lord enables and enjoins, "That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit." (Romans 8:4)

R. C. Sproul teaches,

Christians dare not treat His law lightly, because how we view God’s law indicates how we view God Himself (Rom. 3:21). Thus, Christians are called to joyful obedience to His law out of love for Christ. This obedience bears practical righteousness.

This righteousness is not the basis of our salvation; we cannot merit justification by our works (Rom. 3:21–22). But it exceeds that of the Pharisees because their obedience did not come from the heart. And it is a mark that we have truly been saved and thus will enter the kingdom of heaven. (source)

I have a ways to go practically in heart, and in deed.

Answer 4

John Owen rightly recognized that the New Covenant alone is the Covenant of Grace. It was formally established as a covenant in the death of Christ, but it effectively worked retroactively to save OT saints prior to its legal establishment. Read his tremendous commentary on Hebrews 8 for a great explanation.

https://contrast2.wordpress.com/2010/02/15/john-owens-commentary-on-the-old-and-new-covenants-outline/