“No other religion–whether secularism, Greco-Roman paganism, Eastern religion, Judaism, or Islam–believes God became breakable or suffered or had a body. Eastern religion believes the physical is illusion. Greco-Romans believe the physical is bad. Judaism and Islam don’t believe God would do such a thing as live in the flesh.
But Christmas teaches that God is concerned not only with the spiritual, because he is not just a spirit anymore. He has a body. He knows what it’s like to be poor, to be a refugee, to face persecution and hunger, to be beaten and stabbed. He knows what it is like to be dead. Therefore, when we put together the incarnation and the resurrection, we see that God is not just concerned about the spirit, but he also cares about the body. He created the spirit and the body, and he will redeem the spirit and the body.
Christmas shows us that God is not just concerned about spiritual problems but physical problems too. So we can talk about redeeming people from guilt and unbelief, as well as creating safe streets and affordable housing for the poor, in the same breath. Because Jesus himself is not just a spirit but also has a body, the gift of Christmas is a passion for justice.
But Christians have not only a passion for justice but also the knowledge that, in the end, justice will triumph. Confidence in the justice of God makes the most realistic passion for justice possible.”
Tim Keller in Come, Thou Long-Expected Jesus: Experiencing the Peace and Promise of Christmas, edited by Nancy Guthrie (Crossway Books, 2008).