“The doctrine of the covenant of works, finally, contains a third idea, an idea of the richest religious and ethical significance. Adam was not created alone. As a man and by himself he was incomplete. He lacked something that no lower creature could make up (Gen. 2:20). As a man by himself, accordingly, neither was he yet the fully unfolded image of God. The creation of humankind in God’s image was only completed on the sixth day, when God created both man and woman in union with each other (Gen. 1:27), in his image. Still, even this creation in God’s image of man and woman in conjunction is not the end but the beginning of God’s journey with mankind. It is not good that the man should be alone (Gen. 2:18); nor is it good that the man and woman should be alone. Upon the two of them God immediately pronounced the blessing of multiplication (Gen. 1:28). Not the man alone, nor the man and woman together, but only the whole of humanity is the fully developed image of God, his children, his offspring. The image of God is much too rich for it to be fully realized in a single human being, however richly gifted that human being may be. It can only be somewhat unfolded in its depth and riches in a humanity counting billions of members. Just as the traces of God (vestigia Dei) are spread over many, many works, in both space and time, so also the image of God can only be displayed in all its dimensions and characteristic features in a humanity whose members exist both successively one after the other and contemporaneously side by side. But just as the cosmos is a unity and receives its head and master in humankind; so also that humanity in turn is to be conceived as an organism that, precisely as such, is finally the only fully developed image of God. Not as a heap of souls on a tract of land, not as a loose aggregate of individuals, but as having been created out of one blood; as one household and one family, humanity is the image and likeness of God. Belonging to that humanity is also its development, its history, its ever-expanding dominion over the earth, its progress in science and art, its subjugation of all creatures. All these things as well constitute the unfolding image and likeness of God in keeping with which humanity was created. Just as God did not reveal himself all at once at the creation, but continues and expands that revelation from day to day and from age to age, so also the image of God is not a static entity but extends and unfolds itself in the forms of space and time. It is both a gift (Gabe) and a mandate (Aufgabe). It is an undeserved gift of grace that was given to the first human being immediately at the creation but at the same time is the grounding principle and germ of an altogether rich and glorious development. Only humanity in its entirety--as one complete organism, summed up under a single head, spread out over the whole earth, as prophet proclaiming the truth of God, as priest dedicating itself to God, as ruler controlling the earth and the whole of creation--only it is the fully finished image, the most telling and striking likeness of God.
Scripture clearly teaches all this when it says that the church is the bride of Christ, the temple of the Holy Spirit, the dwelling of God, the new Jerusalem to which all the glory of the nations will be brought. This is the picture, to be sure, of the state of glory that will now be attained through the thickets of sin; but religion, the moral law, and man’s final destiny are essentially the same in both the covenant of works and the covenant of grace. In both the goal and end is a kingdom of God, a holy humanity, in which God is all in all.” - Herman Bavinck, Reformed Dogmatics, Volume 2, Chapter 13 (pp. 576-578)