What does it mean that Jesus is the mediator of the New Covenant (Hebrews 12:24)?

The next thing is, "And to Jesus, the mediator of the new covenant." There is a profound reason for the introduction of this office of Christ in this place. Two things in connection with this subject have been previously taught in this epistle. In Hebrews 8 it is said that Christ, "who is set on the right hand of the throne of the Majesty in the heavens; a minister of the sanctuary, and of the true tabernacle, which the Lord pitched, and not man … has obtained a more excellent ministry, by how much also He is the mediator of a better covenant, which was established upon better promises" (vv. 1, 2, 6); and, furthermore, it is said that the new covenant is made with the house of Israel, although it is ever to be remembered, as 1 Corinthians 11 and 2 Corinthians 3 evidently show, that all believers are brought into the enjoyment of the blessings which the New Covenant secures. Now Christ is both High Priest and Mediator. As the great High Priest He appears before God on our behalf; as Mediator He is the One through whom God has approached man. In other words, God comes out through the Mediator, and man (the believer) goes in through the Priest. And there is to be added to this, that the terms of the new covenant explain God's attitude towards man. For Israel it secures, as may be seen in this chapter, the law written in the heart, and forgiveness of sins; and for all believers now, righteousness and the Spirit, according to the apostle's teaching in 2 Corinthians 3.

It is because of the necessity there was for this sacrifice — the necessity that sins, and finally sin, should be entirely put away, in order to the enjoyment of the eternal promises (for God could not bless, as an eternal principle and definitively, while sin was before His eyes), that Christ, the Son of God, Man on earth, became the Mediator of the new covenant, in order that by death He might make a way for the permanent enjoyment of that which had been promised. The new covenant, in itself, did not speak of a Mediator. God would write His laws on the hearts of His people, and would remember sins no more.

The covenant is not yet made with Israel and Judah. But meanwhile God has established and revealed the Mediator, who has accomplished the work on which the fulfilment of the promises can be founded in a way that is durable in principle, eternal, because connected with the nature of God Himself. This is done by means of death, the wages of sin, and by which sin is left behind; and expiation for sins being made according to the righteousness of God, an altogether new position is taken outside and beyond sin. The Mediator has paid the ransom. Sin has no more right over us.

(V. 15). As the offering of Christ meets the holiness of God and the need of the sinner, Christ becomes the Mediator of the new covenant, the One through whom all blessings of the new covenant are secured for those who are called, that they might enter into the promise of the eternal inheritance.

Christ our Lord is the Mediator of this new covenant. The first covenant, the law, could only condemn; but He by means of His death has redeemed us from the curse of the law: now those who are called have received the promise of an eternal inheritance.

There is Zion on earth, the heavenly Jerusalem above, the general company of angels, and the church of the first-born; then God Himself, and in the way of government, "the judge of all"; then the "spirits of just men made perfect," saints of the Old Testament in the character grace had given them, "or just men." They had run their course and they are there. Then begins what is connected with the earthly part - looking at the effect. We are come "to Jesus the mediator of the new covenant." We are not come to the new covenant, but to Jesus the Mediator of it. I am associated with Him who is the Mediator; that is a higher thing than if merely come to the covenant. He will make this new covenant with Israel on earth. But there is added "And to the blood of sprinkling." The earth will be benefited by the shedding of the blood of Christ: it cries peace instead of vengeance, as Abel's did.

Next we read "and to Jesus, mediator of a new covenant." This is the pledge of the enduring mercy which awaits the two houses of Israel. Of this all the ancient revelation speaks fully, the Law, the Psalms, and the Prophets; so that there is the less need of now dwelling on it particularly, even if the Gospels and the Acts, and the Epistles and the Revelation did not also confirm it. It is only necessary to say here that "new" means "fresh" or "recent," a quite different word and thought from the usual "new" covenant, which means covenant on a new principle, not letter but spirit, not man's responsibility as at Sinai but God's grace in Christ. Here the added comfort is given that when in days to come Jehovah makes the new covenant with the house of Israel and with the house of Judah, when He will put His law in their inward parts and write it in their hearts, and be their God and they His people, with other blessed and abiding consequences, it will also be as "fresh" as when the blood was shed by which the great Mediator founded it on His death before God. The Christian Hebrews had come to Jesus its Mediator, not yet to its actual connection and establishment with Israel, but to Him who has done all for this purpose in due time.

But the prospect makes the way for another consequent blessing: "And to blood of sprinkling speaking better than Abel." If a new covenant points to Israel put under new and sure and everlasting covenant mercy in virtue of Jehovah-Messiah, the voice of the blood of sprinkling does not cry for vengeance and curse as Abel's did (Gen. 4:10-12); it speaks of reconciliation for the earth (and indeed all things) assured by that blood which is alone precious and efficacious with God. It is clear, however, that this, however truly a guarantee, is like others we have seen, not yet in actual accomplishment; if we have come to them in hope, yea in full assurance of hope, we do not yet see them, and so with patience wait for them all, surely to be manifest in the day we see approaching.

In 7:22 the Lord Jesus is the Surety—the guarantee—of a better covenant, a covenant yet to come. In 8:6; 9:15; and 12:24, He is the Mediator of this better, new covenant. In 8:6-13 the beneficiaries of this new covenant are clearly seen to be the two houses of Judah and Israel. And in those same verses, the terms of this new covenant are quoted from Jeremiah 31.

In connection with spiritual blessings, that which the blood of Christ has secured for Israel (His earthly people) under the new covenant has likewise been secured for us, His heavenly people. And further, whilst we have not come to earthly things, and whilst we have not come to the new covenant, amongst the heavenly things we have come to, listed in Hebrews 12, we have come to “Jesus, mediator of a new covenant”. We haven't come to the new covenant—but we have come to the One who is its Mediator! Infinitely greater and more precious to have a personal relationship to Him!

Hence, too, in Heb. 9:15, He says: "For this cause he is the mediator of the new covenant, that by means of death, for the redemption of the transgressions that were under the first covenant, they which are called might receive the promise of eternal inheritance, not the establishment of the new covenant, but "eternal inheritance," as having to do with the Mediator Himself whose blood had been shed.

In this passage we are again pointed to Christ, here as 'mediator of a new covenant'. We had seen Him as mediator (of a 'better' covenant) in chapter 8, verse 6; and we had seen the term 'a better covenant' in chapter 8, verse 8. But what is brought out in a striking manner here is that death was necessary in order for the Lord Jesus to become the mediator of this new covenant.