“If man already stood in a covenant relation to God before the fall, then it is to be expected that the covenant idea will also dominate in the work of redemption. God cannot simply let go of the ordinance which He once instituted, but much rather displays His glory in that He carries it through despite man’s sin and apostasy. It was merely the other side of the doctrine of the covenant of works that was seen when the task of the Mediator was also placed in this light. A Pactum Salutis, a Counsel of Peace, a Covenant of Redemption, could then be spoken of. There are two alternatives: one must either deny the covenant arrangement as a general rule for obtaining eternal life, or, granting the latter, he must also regard the gaining of eternal life by the Mediator as a covenant arrangement and place the establishing of a covenant in back of it. Thus it also becomes clear how a denial of the covenant of works sometimes goes hand in hand with a lack of appreciation for the counsel of peace.”
– Geerhardus Vos, The Doctrine of the Covenant in Reformed Theology
Vos sees the Covenant of Redemption as the economic framework for the forwarding of the eschatological purpose built into the Covenant of Works. As Vos says later in this section, this accords with the Reformed emphasis, over the Lutheran one, that God’s solution to the greatness of our sin and misery is to the end of the glory of the God and not merely a relieved conscience. This is because the Covenant of Redemption locates the furthering of the goal of the broken Covenant of Works in God himself: “The fact that redemption is God’s work by which He wills to be glorified can in no wise be more strongly expressed than by thus exposing its emergence from out of the depths of the divine Being Himself.”
There’s so much in this essay, it’s mind boggling. I highly recommend you read it.