There are plenty of clues out there to convince us that whatever happened was important. The first affects everyone’s lives, Christian or not: the year. To this day, though most western governments pride themselves on a detachment from religion, Christmas remains the great pillar in time that splits our counting of the years in two. Instead of reckoning the year based on whatever consul or emperor held power as the Romans did, Christians sought a Christ-based chronology. This slowly led to the widespread use of B.C. (“before Christ”) and A.D. (“anno domini”, i.e., “the year of the Lord”) by the 17th century (and in many places, much earlier). Even the secular equivalent, B.C.E/C.E, only changes the terminology – history still hinges on Jesus.
In addition, for Bible readers, Jesus’ birth marks the renewal of inspired literature, ending a more than 400-year dearth between the last book of the Old Testament, Malachi, and the first book of the New Testament, Matthew. But why this literary and chronological separation? What distinguishes the Old from the New?
In the Old Testament, we find books of law, history, poetry, and prophecy. Yet they all work together to tell the single story of fallen humanity, the specially chosen but unreliable people of Israel, and God’s faithful work to reconcile them to himself. In Jeremiah, with Israel’s conquerors practically at Jerusalem’s gate, God reveals his wildest dream: “I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people… For I will forgive their iniquity, and I will remember their sin no more” (Jer. 31:31,33,34). Other prophets repeat similar promises, and Isaiah adds tantalizing details, like, “a virgin shall conceive and bear a son, and shall call his name Immanuel” (Is. 7:14). So, as the ink of Malachi’s final words dried on the scroll, Israel looked forward to the fulfillment of God’s word, clinging to the Law and the Promises of God.
Long years of waiting bring us to Christmas and the beginning of the New Testament. But instead of searching Matthew or Luke’s wonderful narratives for details, we’ll use John’s universe-wide lens to study what happened on Christmas: “And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth” (Jn. 1:14). Here, let’s pause to study the Greek noun imperfectly rendered “word” in English: logos (λόγος). One could use logos in a wide variety of ways, explaining why it hogs half a page in a Greek Lexicon. But since John 1 contains the world’s most awe-inspiring philosophical text, let’s use the philosophical definition of logos: “the intelligible law of the universe,” which stoics believed “prompted the regular motions of the heavenly bodies and the exact functioning of natural objects.” John 1 would have stupefied the pagan philosopher, and should still stupefy us today, by stating, “In Christ, the unique Son of God, the cosmological λόγος was incarnate.” John’s logos was with God in the beginning and made all things. It is life and the true light, “full of grace and truth.” It is God (Jn. 1:1-14). And it became flesh on Christmas day, so much power dwelling in the fragile body of a newborn infant. This is what happened on Christmas.
But how does this event correspond to the Law and Promises of God displayed in the Old Testament? Let the words of Christ himself reassure us of His faithfulness: “Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them” (Matt. 5:17). First, this statement deals with the Law. As the logos incarnate, Christ fulfills the Law. The Greek here, pléroó (πληρόω) means “to make full, to complete.” For instance, one can pléroó an empty jar with water or an empty basket with food. Likewise, Christ completes the written law by becoming the living law. What may have appeared rigid and distant on tablets of stone becomes interactive and intimate in Christ. “In the law, considered merely as a code, we have only the form of truth, but Christ is the Truth… He came to do the will of God, so that the same law might be written in our hearts, and that we might be restored to the blessedness of doing God’s will; that the form might become the reality in us.” That which appeared as ‘rules’ on tablets of stone turns out to be pure, selfless love in Christ incarnate. In this way, Christ enriches and fulfills the law.
Just as He did for the Law, Christ came to pléroó the promises of God as described by Old Testament prophets. The gospels constantly remind us of this. For instance, in Luke 4:16-21, Jesus stands up and reads a passage from Isaiah 61:1-2, sits down, and says, “Today this Scripture has been fulfilled in your hearing.” But He doesn’t stop there. Both directly and through His apostles, Jesus declares new promises. These combine harmoniously with outstanding Old Testament prophecies to comprise End Time Prophecy. As a result, one can summarize the Old and New Testaments and the impact of Christmas as follows:
All this leads to one crucial truth: on Christmas, God pioneered a new pathway for humanity, an alternative to the doom under which we had suffered since Adam and Eve fell. Christ’s death and glorious resurrection sealed this pathway for us: “But in fact Christ has been raised from the dead, the first fruits of those who have fallen asleep. For as by a man came death, by a man has come also the resurrection of the dead. For as in Adam all die, so also in Christ shall all be made alive” (1 Cor. 15:20-22). In faith we can accept this gift of true humanity from God, “for in Christ Jesus you are all sons of God, through faith” (Gal. 3:26). And, just as Israel longed for the Messiah’s first advent, we eagerly await His second advent, the Son of Man coming with the clouds (Dan. 7:13). God will fulfill outstanding promises, renew the earth, and descend to dwell with us (Rev. 21:33), just as he dwelt with us many years ago, the day when angels announced, “Do not be afraid! For behold, I bring you good news of great joy that will be for all people: Today in the city of David a Savior has been born to you. He is Christ the Lord!” (Luke 2:10-11).
 W.W. Tarn & G.T. Griffith. (1970). Logos. In The Oxford Classical Dictionary. (p. 618). New York: Oxford University Press
 Strong’s Concordance
 Fred Bischoff, ed., 1895 Evangelism Resources from a Period of “Manifest Demonstration of the Spirit”: The W.W. Prescott Armadale Sermons Melbourne, Australia (1888 Glad Tidings: Berrien Springs, 1999), 74.