Athanasius has a nice answer;
When a great king has entered a large city and taken up residence in one of the houses in it, such a city becomes worthy of great honor an d is no longer assaulted by any enemy or bandit descending upon it, but rather is deemed worthy of every attention because of the king residing in one of its houses. Such is the case with the king of all. As soon as he came to our realm and took up residence in one body like our own the whole conspiracy against humanity by its enemies has been stopped and the corruption of death which had formerly ruled over them has been obliterated.
On the Incarnation, 9 (cited in Khaled Anatolios, Athanasius, p. 60-61)