When one considers the glory Christ had with God before time began and throughout the Old Testament, it may at first seem strange that He would have so willingly stepped down from Heaven to take on the form of humanity. Paul tells us, however, that not only can we know the intentions of Christ in doing so; we must emulate such an attitude in our own lives (Php 2:5-8).
The first great aspect of the incarnate Christ is that He is completely God. From conception it was understood that the Child being born to Mary and Joseph was not merely a son, He is the Son of God (Luk 1:35). As God Himself Christ has authority over demons (Mat 8:29; Luk 4:41; 8:28), He broke the bonds of death through His resurrection (Rom 1:4), He destroyed the work of the Devil by providing the means of salvation (1Jo 3:8; Joh 3:18; 1Jo 5:20) and He continues to work through the good news we speak today (Mar 1:1; Act 9:20; 2Co 1:19). As the Son of God Christ is the perfect reflection of God Himself approaching man with the means of reconciliation by coming in the flesh, suffering, being tempted and sacrificing Himself for our salvation from sin, sanctification in life and liberation from death (Heb 2:10-18).
The second great aspect of the incarnate Christ is that He is completely human. In other words, Christ is the "true man" and reflects humanity as God intended it to be. This is why Christ is so often called the Son of Man. Jesus enjoyed food and drink (Mat 11:19), He required rest (Luk 9:58) and He ultimately suffered and died at the hands of some of the very men He sought to save (Mat 20:18; Luk 19:10). That any man should suffer such a fate is reason enough for amazement but this Man who suffered so much is the Messiah (Mat 16:13-18) and the King (Mat 16:28) who deserves our service and sacrifice. Christ then as the Son of Man is the means by which man has been reconciled to God; a role only He could have fulfilled. For "just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned...much more did the grace of God and the gift by the grace of the one Man, Jesus Christ, abound to the many" (Rom 5:12, 15, NASB throughout).
Finally, since He is both completely God and completely human, Jesus Christ is "the actuality of reconciliation." In other words, because of the work of Jesus as the incarnate Christ reconciliation is not just a theological theory or proposition, it is an historical fact. It is because of this that Paul could write to the church at Rome that "the righteousness of God has been manifested...by His grace through the redemption which is in Christ Jesus; whom God displayed publicly as a propitiation in His blood...so that He would be just and the justifier of the one who has faith in Jesus" (Rom 3:21-26).
In Christ, then, God has reconciled humanity to Himself (Rom 5:10-11; Col 1:19-22), Humanity has reconciled Himself to God (Act 2:22-36), humanity has been reconciled to himself (Eph 2:14-16) and we have been entrusted with His message of reconciliation. "Now all these things are from God, who reconciled us to Himself through Christ and gave us the ministry of reconciliation, namely, that God was in Christ reconciling the world to Himself" (2Co 5:18-20).
Outline adapted from Karl Barth, "Lord as Servant, Servant as Lord," in Readings in Christian Theology, ed. Peter C. Hodgson and Robert H. King (Philadelphia: Fortress Press, 1985), pp. 226-232.
Barth, p. 231, emphasis added.