As we celebrate the Nativity of Jesus Christ, the birth of God the Son into his world, here’s one question to hold meditatively in our minds and hearts over the coming days: why did God become a man? This is, of course, the title of St. Anselm’s classic eleventh-century treatment of the incarnation: Cur Deus Homo, Why God Became a Man. But it’s a question that many have taken up before and since. The place to begin when answering this question is our Lord’s own words about his incarnational mission. As we read the gospels and study just the times that Jesus explicitly says “I have come” or “the Son of Man came,” a multi-faceted portrait emerges. Jesus tells us that he came, among other things:
- To fulfill the Law and the Prophets (Matt 5:17)
- To do the will of the Father (John 6:38)
- To bear witness to the truth (John 18:37)
- To serve and to give his life as a ransom (Mark 10:45)
- To seek and to save the lost (Luke 19:10)
- To bring a sword of division, that is, to bring all humanity to a crisis point over his identity and mission (Matt 10:34-35)
Anselm’s own answer to the question had to do with the connection between the incarnation and the atonement: God became man because only the God-Man could make satisfaction for sins. Only God could repair the infinite breach caused by humanity’s dishonoring of God. But only a human could die on behalf of and in the place of fallen humanity. Indeed, the atonement is the principal purpose of the incarnation that we encounter in Scripture. But it’s not the only one, as the list above from Jesus’ own lips demonstrates.
In his treatment of the necessity of the incarnation in the Summa Theologiae, Thomas Aquinas offers a ten-fold purpose of the incarnation. While Thomas does not think that the incarnation was absolutely necessary for the redemption of humanity (because God is omnipotent and could have devised many other ways—a point that Anselm before him and some Reformed theologians after him would dispute), he does think that the incarnation was necessary in the sense of being the most fitting (conveniens) way for God to accomplish human salvation. Why? Because the incarnation is most useful both for our “furtherance in the good” and for our “withdrawal from evil.” On each of those points, Thomas offers five further explanations for a total of ten reasons God became incarnate:
Furtherance in the good:
- To make certain our faith in God
- To strengthen our hope that God loves even sinners like us
- To enkindle our love
- To give us an example to imitate
- To cause us to participate in the divine life, which is our true and final bliss
Withdrawal from evil:
- To teach us to reject the devil
- To teach us humanity’s dignity
- To show us that only God’s grace can accomplish salvation
- To cure our pride
- To free us from sin through the satisfaction of the God-Man (here, Thomas marshals an argument similar to Anselm’s).
So, to summarize, Thomas teaches that God became man in order to give us faith, hope, love, an example, divinization and beatitude, victory, dignity, grace, humility, and atonement. What glory! What grace! What mind-bending mystery! That one of the Trinity would become a human to make humanity one with God!