Men (sinners) have always been reconciled to God the Father consistent with the sovereign covenants that He as established throughout redemptive history.
A covenant always includes an “agreement” with conditions/requirements to which the parties of the covenant are bound. Violating the terms of the covenant invoke consequences stipulated within the covenant – generally curses. Conformance with the covenant also invokes consequences stipulated within the covenant – conditional promises, blessings.
I place “agreement” in quotes because the biblical covenants are generally NOT agreements established between participants in the way we would generally understand a contract today. Rather, the covenant is generally established by the sovereign one involved in the covenant that has authority over other participants in the covenant.
The first covenant declared in history was the Covenant of Works established by God with Adam. God promised eternal life (salvation/preservation) if Adam would refrain from eating the fruit of the tree of knowledge of good and evil (i.e., be obedient). Death - spiritual and physical, upon Adam and his descendants was to be the cost of disobedience.
The next covenant was declared (often ascribed the title of The Covenant of Grace) soon after Adam's fall. God declared in Gen 3:15 that he would provide a redeemer that would overcome the works of Satan (i.e., he would, once and for all, overcome the result of sin - death). Trusting in THIS promise, God's provision of a redeemer that would overcome the death resulting from sin, was saving faith from the time of its declaration until today - the means by which it was accomplished being revealed with ever-increasing clarity.
Next, a non-salvific covenant (a covenant of common grace) was declared unto Noah - God would sustain His creation until the redemption declared in Gen 3:15 was bought to completion. God would (despite the depravity of man) preserve His creation (maintaining the seasons, and human governance) until the consummation of the Covenant of Grace (which we now Know is accomplished in the second coming of Messiah and the new heaven and new earth).
Later, God established his covenant with Abraham, in which God did not work out a deal with the man. He sovereignly told Abraham what he (God) was going to do. God declared that he would bless Abraham with a land and a Seed, and by that Seed all of the nations of the earth would be blessed. The provided further information regarding how the promise of Gen 3:15 was going to play out. Still, faith in God's gracious provision of salvation through a redeemer was saving faith - in some way still not totally clear (the full clarification would not come until the Holy Spirit worked in Paul to write Gal 3).
Later, God would establish another covenant with the people of Israel. This was a law covenant that was brought to the people through Moses, so we refer to it as the Mosaic Covenant (MC). But this Mosaic Covenant did not put an end to the Abrahamic Covenant (AC). This is why Moses pleaded with God with regards to the promise (covenant) made to Abraham, Isaac, and Jacob – the covenant of the seed - immediately AFTER having received the Law from God and the people were worshiping the golden calf. Both the MC and the AC were moving through history
together - MC largely of law, and AC purely of grace.
When Paul wrote that Jesus was that Seed of the AC, and all those that were “in Christ” were children of the promise to Abraham (Gal 3) showing us that even the cross of Christ did not put an end to the Abrahamic Covenant. Rather, it was the consummation of that gracious covenant – that promise made to Abraham.
When we see writing in Scripture referring to “The Old Covenant” and “The New Covenant,” the distinction is generally between the laws and statutes of the MC under which Jesus, as a Jewish man, lived (and obeyed perfectly) and the AC which Jesus fulfilled as that Seed through whom every nation would be blessed – for he would bring into right relationship with God men of every tongue and tribe and nation.
Men now live under one of two Covenants
- The Covenant of Works make with Adam – Which he broke. A covenant more broadly expressed in the subset of laws given to Moses, the subset we call the 10 Commandments.
- The Covenant of Grace, first expressed vaguely in God’s promise that he would send one that would crush the head of the serpent. Later given further revelation as the Seed promised to Abraham – one that would bless all nations. Still later given fuller expression as the fulfillment of the promise (covenant) made with King David that his thrown would be eternal and he would have a righteous descendant that would reign eternally upon that thrown, an eternal son of David. A son that would build a house for God – that house being a people of God – even those in Christ and children of the promise made to Abraham. All this came to fruition when Jesus died, was buried, and rose again – paying the price of the sins of the elect.
Men are born under the Covenant of Works - Condemned by the Law.
If they come to faith in Christ, the one who obeyed the law perfectly, they are no longer condemned under the law. Their sin debt was paid by Christ's sacrifice and His righteous obedience is credited to them. They are saved by grace through faith, and that . . .
To be clear, the plan to redeem a people by the sacrifice of God the Son (to provide an exit for some from the sure damnation which comes from the covenant of works) was not formulated at the time of the garden fall. Rather, it was formulated in eternity past. It was formulated when a covenant was made between coequals before the foundation of the world – a covenant between God the Father, God the Son, and God the Holy Spirit. A covenant that is necessarily inferred from the following:
Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ: According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love: Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will, To the praise of the glory of his grace, wherein he hath made us accepted in the beloved. (Eph 1:3 – 6)
This is Covenant Theology in a nutshell. From before Genesis to revelation it is one story of God working out the redemption of His people through the sacrifice of God the Son - One Story - One Savior. My apologies to my reformed brothers for the shortcuts and abbreviations.