When we think of Christmas, we often think of the beginning of Jesus’ life here on earth, of when he was incarnate in the flesh and the beginning of the story of the Gospels. But we don’t often think of Christmas as an Eschatological event. The historical reality of the incarnation wasn’t just a sign of a new beginning, but of a completion and fulfillment. Christmas is a mark of the end, the eschaton, as the God who will bring the final day steps into time and space to begin the culmination of all things. With him comes light and peace and hope; and also judgment and terror, and finality. Far from a celebration of just a cute little baby that we call Jesus, Christmas shows us the declarative and magnificent power of the omnipotent God who reigns over all things. Christmas is the beginning of the end.
Usually 1 Corinthians 15:45-49 does not come to mind as a Christmas passage, but here we see the eschatological nature of the incarnation of Christ. In fact, the passage itself is set within the context of the great eschatological truth about the nature of Christ’s resurrection and its connection the future resurrection of all those who are united to Christ.
Thus it is written, ‘The first man Adam became a living being’; the last Adam became a life-giving spirit. But it is not the spiritual that is first but the natural, and then the spiritual. The first man was from the earth, a man of dust; the second man is from heaven. As was the man of dust, so also are those who are of the dust, and as is the man of heaven, so also are those who are of heaven. Just as we have borne the image of the man of dust, we shall also bear the image of the man of heaven.
Adam was the real, historical, flesh and blood type of the prophesied antitype, Jesus Christ. The first (πρῶτος, protos) Adam was the beginning of the human race and his work necessitated redemption; the last (ἔσχατος, eschatos) Adam was the completion of the human race and his work brought about redemption. The Incarnation of Jesus was the event by which a new humanity was brought forth as the first fruits of Christ’s life, death and resurrection. This new humanity participates in the eschaton today and is continually sanctified until its ultimate completion is fully realized.
This new humanity shares in the nature of the eschatos-Adam, just as how all humanity derives its nature from the proto-Adam. Morris observes, “The first Adam passed on his nature to those who came after… Adam was the progenitor of the race, and his characteristics are stamped on the race. In the same way, Christ is the last Adam, the progenitor of the race of spiritual people… By virtue of his office as the last Adam he stamps his characteristics on those who are his.”
The eschatos-Adam not only brought the heavenly into the earthly because of his presence on earth, but he also continues to bring the heavenly into the earthly by his work of regeneration. In his work of salvation the eschatological declaration of justification is made, the future glorified man is formed in sanctification and the reality of our future resurrection becomes the current grounding of our present hope. Calvin puts it well, “As the animal nature, which has the precedency in us, is the image of Adam, so we shall be conformed to Christ in the heavenly nature; and this will be the completion of our restoration. For we now begin to bear the image of Christ, and are every day more and more transformed into it; but that image consists in spiritual regeneration. But then it will be fully restored both in body and in soul, and what is now begun will be perfected, and accordingly we will obtain in reality what we as yet only hope for.”
Christ is not simply one in a long line of “Adams” of which there are more to come. As the eschatos-Adam he is the final Adam. There will be no more after him, thus all are either only partakers of the proto-Adam’s nature or they also partake of the nature given from the eschatos-Adam. Christ’s people, the Church, are an eschatological people living in this present age. There does not exist a plethora of “Adams” and so each person’s identity in humanity can only come from a limited number of sources. Each of us must be sure of which Adam we are a partaker of. Some are only partakers of the incomplete and sinful First Man, but Christ’s people are partakers of the Eschatological Man, the man Jesus Christ.
In Christ the fullness of time meets us in the baby of the incarnation, the fullness of God meets us in his righteous power, and the fullness of humanity meets us in him as the last Adam. So this Christmas, remember the eschatological reality of the incarnation, as eternity and finitude exist together in a divine mystery. Jesus was born of Mary to bring about the redemption of human kind, not merely to restore us to the proto-Adam, but to regenerate us into partakers of the eschatological Adam.
Adam’s likeness, Lord, efface,
Stamp Thine image in its place:
Second Adam from above,
Reinstate us in Thy love.
Let us Thee, though lost, regain,
Thee, the Life, the inner man:
O, to all Thyself impart,
Formed in each believing heart.
-The last verse of Hark! the Harold Angels Sing
 Leon Morris, Tyndale New Testament Commentaries: 1 Corinthians (Grand Rapids: William B. Eerdmans, 2000), 223-224.
 Henry Beverudge, Esq., trans. John Calvin’s A Commentary of Saint Paul’s Epistle to the Corinthians (Grand Rapids: Baker Books, 2003) 492.