God’s love and God’s law are eternal and eternally united because God is eternally Triune. The Father is not the Son or the Spirit. The Son is not the Father or the Spirit. The Spirit is not the Father or the Son. Thus, each Person is the eternal Godhead is eternally distinct from the other two Persons. Because the Father is not the Son or Spirit, nor is the Son the Father or Spirit, nor is the Spirit the Father or the Son, therefore, in accordance with the eternal Covenant each owns distinct, ie, private property. “You shall not steal, nor deal falsely, nor lie to one another … You shall not cheat your neighbour, nor rob him” Exodus 19:11;13a.
Eternally the Father loves the Son and the Spirit. Eternally the Son loves the Father and the Spirit. And eternally the Spirit loves the Father and the Son. Thus the Father and the Son and the Holy Spirit are God and Their bond of love and law, their Covenant bond, is eternal. It is the eternal love in the Godhead that God sheds abroad in time in terms of His eternal Covenant. “Father, that they also whom You gave Me may be with Me where I am, that they may behold My glory which You have given Me: for You loved Me before the foundation of the world” John 17:24.
The Triune God is eternally one. Therefore God eternally loves God and His neighbour as Himself. “The first of all the commandments is: ‘Hear, O Israel, the LORD our God, the LORD is one. And you shall love the LORD your God with all your heart, with all your soul, with all your mind, and with all your strength.’ And the second, like it, is this: ‘You shall love your neighbour as yourself.’ There is no other commandment greater than these” Mark 12:29-31.
The eternally Triune God created Adam with His eternal Covenant Law on Adam’s heart, ie, the Ten Commandments written in positive terms, the summary of which is: “Love God and your neighbour as yourself.” Like the Triune God in whose image he was made, Adam was to mirror God on earth by loving God and His neighbour as himself. Thus, with God’s Law written internally, Adam was also given an outward command to test his faithfulness to the Covenant. “Of every tree in the garden you may freely eat, but of the tree of the knowledge of good and evil you shall not eat, for in the day you eat of it you shall surely die” Gen. 2:16-17.
When Adam broke this pre-Fall application of God’s eternal Covenant, commonly referred to as the Covenant of Works, God in accordance with His love, immediately applied His eternal Covenant to Adam, this time as the Covenant of Grace. Thus Adam was no longer on probation, having broken its terms by eating the forbidden fruit. However, God’s Covenant justice must also be met. Therefore, since Adam had incurred the Covenant of Work’s penalty, ie, death for himself and all he represented, all mankind in him, mankind was plunged into an estate of sin, misery, and death. “The earth is defiled under its inhabitants, because they have transgressed the laws, changed the ordinance, broken the everlasting covenant” Isaiah 24:5.
As the new Adam, Jesus Christ, being both God and Man, is God and Man in covenant forever. As a Man He satisfied God’s justice by keeping God’s Covenant Law perfectly and also paid the death penalty the first Adam incurred for breaking it. Thus Jesus is the new Federal or Covenant Head of (redeemed) mankind. The eternal Covenant between the Father and Son (as witnessed to by the Holy Spirit and the (written) Word or Covenant) is referred to as the Covenant of Redemption: whereby Christ redeems a people innumerable chosen by the Father before the foundation of the world. Thus in the eternal Covenant the Father represents the Triune God and the Son represents mankind. “Just as He chose us in Him before the foundation of the world” Eph. 1:4a. “After these things I looked, and behold, a great multitude which no one could number, of all nations, tribes, peoples, and tongues, standing before the throne and before the Lamb, clothed with white robes, with palm branches in their hands, and crying out with a loud voice, saying, ‘Salvation belongs to our God who sits on the throne, and to the Lamb!’” Rev. 7:9-10. “The Lamb slain from the foundation of the world” Rev. 13:8b.
The compilers of the Westminster Confession of Faith (1647) refer to the Covenant of Redemption and Grace in their “THE SUM OF SAVING KNOWLEDGE” thus:
The remedy provided in Jesus Christ for the elect by the covenant of grace.
“O Israel, thou hast destroyed thyself; but in Me is thine help.” Hos.13:9.
I. ALBEIT man, having brought himself into this woeful condition, be neither able to help himself, nor willing to be helped by God out of it, but rather inclined to lie still, insensible of it, till he perish; yet God, for the glory, of his rich grace, hath revealed in his word a way to save sinners, viz, by faith in Jesus Christ, the eternal Son of God, by virtue of, and according to the tenor of the covenant of redemption, made and agreed upon between God the Father and God the Son, in the council of the Trinity, before the world began.
II. The sum of the covenant of redemption is this: God having freely chosen unto life a certain number of lost mankind, for the glory of his rich grace, did give them, before the world began, unto God the Son, appointed Redeemer, that, upon condition he would humble himself so far as to assume the human nature, of a soul and a body, unto personal union with his divine nature, and submit himself to the law, as surety for them, and satisfy justice for them, by giving obedience in their name, even unto the suffering of the cursed death of the cross, he should ransom and redeem them all from sin and death, and purchase unto them righteousness and eternal life, with all saving graces leading thereunto, to be effectually, by means of his own appointment, applied in due time to every one of them. This condition the Son of God (who is Jesus Christ our Lord) did accept before the world began, and in the fulness of time came into the world, was born of the Virgin Mary, subjected himself to the law, and completely paid the ransom on the cross: But by virtue of the foresaid bargain, made before the world began, he is in all ages, since the fall of Adam, still upon the work of applying actually the purchased benefits unto the elect; and that he doth by way of entertaining a covenant of free grace and reconciliation with them, through faith in himself; by which covenant, he makes over to every believer a right and interest to himself, and to all his blessings.
III. For the accomplishment of this covenant of redemption, and making the elect partakers of the benefits thereof in the covenant of grace, Christ Jesus was clad with the threefold office of Prophet, Priest, and King: made a Prophet, to reveal all saving knowledge to his people, and to persuade them to believe and obey the same; made a Priest, to offer up himself a sacrifice once for them all, and to intercede continually with the Father, for making their persons and services acceptable to him; and made a King, to subdue them to himself, to feed and rule them by his own appointed ordinances, and to defend them from their enemies.