The first covenant we consider in the scope of Reformed theology does not directly include human beings, but is nevertheless critically important. The covenant of redemption involves the parties who work together to effect human redemption: the Father, the Son and the Holy Spirit. This covenant is rooted in eternity. God’s plan of redemption was no afterthought, designed to repair a creation run amuck. With the eternal and omniscient God, there is no such thing as “plan B.” God worked out his plan of redemption before creation and even before the fall, though he conceived this plan in light of man’s fall and designed it to effect redemption from the fall.
Sproul, R.C.; Grace Unknown: The Heart of Reformed Theology; Baker Books; Grand Rapids, MI; copyright 1997; p. 108