The preparation we Christians have to make consists in this: that we need to have a very clear sense of the stunning, radical character of the truth at the core of our faith: that God became human.

Although we do not live in a country with an established (official) religion, our lived experience of Christianity in general, and of Catholic Christianity in particular, may leave us with a sense that the most extraordinary truth of our faith is as obvious as the numerous churches we see every day. We consider the celebration of Christmas to be a nearly-universal observance. Therefore, the birth of that baby at Bethlehem becomes for us something expected, institutionalized, downright banal.

But if we are to appreciate our own faith — and if we are to appreciate the different belief systems of others — we must consider how unthinkable this idea of God becoming man is. We must even consider how such an idea is a break from the faith-environment from which we have sprung.

We are heirs of the experience of the people of Israel. And what is the dominant theme of that experience? Again and again, the patriarchs and prophets stressed: Your God is not like the gods of the nations that surround you. Those around you indulge their folly by imagining that they have various gods, whose images they make, and whose aid they seek to obtain. They are deluded. There is only one God. You cannot control the one God. It is an insult to presume that you could fashion an artistic representation of God.

Christianity is born — a group of people who knew a man named Jesus. He was killed and was buried, but he rose from the dead. These people claim that this Jesus is the fulfillment of all the aspirations of the children of Israel. They say he is the "anointed one" for whom people had been yearning for centuries. They call him Lord and Master. They go so far as to affirm that he is God.

So someone is identified who meets the expectations of religious yearning yet at the same time contradicts them. After all the centuries of stressing "God is one," "God is almighty," and "God cannot be portrayed," how can people assert that God himself became a member of the human race?

Once, in an oral exam in theology when I was in the seminary, the professor asked me about how God and human beings are united. I cannot recreate exactly what we said to each other, but I came away with a gesture which I find myself, to this day, making when I am deep in thought. I found myself engaging in the act of taking one of my hands to examine the other hand. The Word Made Flesh, I reflected, has united himself with the human race in a startling, audacious way. He united himself with us and he will never dissolve this union.

We Christians do not enter into conversation with non-Christians assuming that we have news of something reasonable which anyone can easily accept. We must be aware of how emotionally charged the idea of the Incarnation (God-made-human) is. We carry with us our conviction that we needed God to do this. This conviction then carries us.