The Fact of Christ's Birth Organizes the Universe Around a New Axis

...Christianity is not something  verbal, something that belongs to the sphere of words. Neither is it a doctrine or,...a message. It presents itself...as a fact...as something that happened, as much more than a verbal message that was written down and that would count as a doctrine, or even a system. Msgr. Giussani does not speak of Christianity but of what he calls the Christian fact. ... what we are dealing with in Christianity is not a doctrine, but a person who must be taken as such and for whom one must make space in one's life.  To convey this idea Giussani uses a splendid metaphor describing how the birth of a child forces the entire universe of a family to reorganize: "When a child is born into a family, it is clear to the parents, to the grandparents, to the whole family and to friends that this is a fact. There is nothing to dispute: a new bed is needed. Perhaps another bedroom; we have to give thought to how to take care of the new arrival; we are concerned about feeding, clothing, and protecting him or her; we get up at night if he or she needs us. The shape of daily life is transformed by virtue of this fact...Christianity is a fact in the very same way. It entered history just as a child enters the house of a husband and wife. Christianity is an irreducible event, an objective presence that desires to reach man; until the very end it means to be a provocation to him and to offer a judgment of him." 

 A Generative Thought, edited by Elisa Buzzi, Chapter Two: Christianity: a Fact in History,  p.35