Fr. Richard Niehaus tells us he is working on a new book in which he'll reflect on the Christian experience of being aliens in this world. In a column at First Things he refers to The Letter to Diognetus, one of the documents that has survived from the first century AD.

The letter was written by a Christian, possibly toward the end of the first century, to Diognetus, a pagan who was curious about the way Christians thought of their place in the world. The author explains:

Though they are residents at home in their own countries, their behavior there is more like that of transients; they take their full part as citizens, but they also submit to anything and everything as if they were aliens. For them, any foreign country is a homeland, and any homeland is a foreign country.

The author goes on to point out that Christians reject certain practices of the Roman world. For instance, they refuse to abort their children or to practice infanticide by exposing their children to the elements, as was common among the Romans. Christians recognize, says the letter writer, that they are viewed as alien, and are not intimidated by that. On the contrary, they rejoice in it. As the soul is to the body, so are Christians to the world. As the Letter to Diognetus puts it, “The soul is captive to the body, yet it holds the body together. So Christians are held captive to the world, and yet they hold the world together.” And that is because they are the bearers of the true story of the world, whether the world wants to know it or not.