Stanford, Calif.

We are in Advent, but over the transom has come the sobering news that Image Books has just published a book written by the pope, “Jesus of Nazareth: The Infancy Narratives,” in which he observes that there was neither an ox nor a donkey in the stable where Jesus was born. Nor did a host of angels sing. They spoke.

Is “Hark! the Herald Angels Sing” doomed?

In fact, the news is not so grim. This is not an encyclical; the pope is writing as Joseph Ratzinger. It turns out that he tolerates, even encourages, the presence of lowing animals in the manger. He writes: “In the Gospel there is no reference to animals at this point. But prayerful reflection, reading Old and New Testaments in the light of one another, filled this lacuna at a very early state by pointing to Isaiah 1:3: ‘The ox knows its owner, and the ass its master’s crib, but Israel does not know.’ ” A few pages later, the pope explains that “Christianity has always understood that the speech of angels is actually song.”

But the clear point of the book — and of the biographical trilogy that this volume completes — is that Roman Catholics should know what the Gospels say about Jesus and stick to it. They should not be distracted by popular myth, or even by historical scholarship.

Evangelical Christianity is supposed to cleave to the text even more exactly. Most evangelicals describe the Bible as literally true. Yet for many, “literally” often means “keep what’s there and add details to make it vivid.”