A crucial event for the church’s confession of the doctrine of the Incarnation came at the Council of Chalcedon (A.D.451), when the church countered both the Nestorian idea that Jesus was two personalities the Son of God and a man under one skin, and the Eutychian idea that Jesus’ divinity had swallowed up his humanity. Rejecting both, the council affirmed that Jesus is one divine-human person in two natures (i.e., with two sets of capacities for experience, expression, reaction, and action); and that the two natures are united in his personal being without mixture, confusion, separation, or division; and that each nature retained its own attributes. In other words, all the qualities and powers that are in us, as well as all the qualities and powers that are in God, were, are, and ever will be really and distinguishably present in the one person of the man from Galilee. Thus the Chalcedonian formula affirms the full humanity of the Lord from heaven in categorical terms.
The Incarnation, this mysterious miracle at the heart of historic Christianity, is central in the New Testament witness. That Jews should ever have come to such a belief is amazing. Eight of the nine New Testament writers, like Jesus’ original disciples, were Jews, drilled in the Jewish axiom that there is only one God and that no human is divine. They all teach, however, that Jesus is God’s Messiah, the Spirit-anointed son of David promised in the Old Testament (e.g., Isa. 11:1-5; Christos, “Christ,” is Greek for Messiah). They all present him in a threefold role as teacher, sin-bearer, and ruler””prophet, priest, and king. And in other words, they all insist that Jesus the Messiah should be personally worshiped and trusted””which is to say that he is God no less than he is man. Observe how the four most masterful New Testament theologians (John, Paul, the writer of Hebrews, and Peter) speak to this.
John’s Gospel frames its eyewitness narratives (John 1:14; 19:35; 21:24) with the declarations of its prologue (1:1-18): that Jesus is the eternal divine Logos (Word), agent of Creation and source of all life and light (vv. 1-5, 9), who through becoming “flesh” was revealed as Son of God and source of grace and truth, indeed as “God the only begotten” (vv. 14, 18; NIV text notes). The Gospel is punctuated with “I am” statements that have special significance because I am (Greek: ego eimi) was used to render God’s name in the Greek translation of Exodus 3:14; whenever John reports Jesus as saying ego eimi, a claim to deity is implicit. Examples of this are John 8:28, 58, and the seven declarations of his grace as (a) the Bread of Life, giving spiritual food (6:35, 48, 51); (b) the Light of the World, banishing darkness (8:12; 9:5); (c) the gate for the sheep, giving access to God (10:7, 9); (d) the Good Shepherd, protecting from peril (10:11, 14); (e) the Resurrection and Life, overcoming our death (11:25); (f) the Way, Truth, and Life, guiding to fellowship with the Father (14:6); (g) the true Vine, nurturing for fruitfulness (15:1, 5). Climactically, Thomas worships Jesus as “my Lord and my God” (20:28). Jesus then pronounces a blessing on all who share Thomas’s faith and John urges his readers to join their number (20:29-31).
—Concise Theology: A Guide To Historic Christian Beliefs (Tyndale House, 2011), pp. 105-106