3 But wherefore, it may be said, is the young Child sent into Egypt? In the first place, the evangelist himself has mentioned the cause, saying, “That it might be fulfilled, Out of Egypt have I called my Son.” And at the same time beginnings of fair hopes were thenceforth proclaimed before to the world. That is, since Babylon and Egypt, most in the whole earth, were burnt up with the flame of ungodliness, He, signifying from the first that He means to correct and amend both, and inducing men hereby to expect His bounties in regard of the whole world likewise, sent to the one the wise men, the other He Himself visited with His mother.
And besides what I have said, there is another lesson also, which we are hereby taught, tending not slightly to true self-command in us. Of what kind then is it? To look from the beginning for temptations and plots. See, for instance, how this was the case even at once from His swaddling clothes. Thus you see at His birth, first a tyrant raging, then flight ensuing, and departure beyond the border; and for no crime His mother is exiled into the land of the barbarians: that you, hearing these things (supposing you thought worthy to minister to any spiritual matter, and then to see yourself suffering incurable ills, and enduring countless dangers), should not be greatly troubled, nor say, “What can this be? Yet surely I ought to be crowned and celebrated, and be glorious and illustrious for fulfilling the Lord's commandment:” but that having this example, you might bear all things nobly, knowing that this especially is the order of all things spiritual, to have everywhere temptations in the same lot with them. See at least how this is the case not only with regard to the mother of the young Child, but also of those barbarians; since they for their part retire secretly in the condition of fugitives; and she again, who had never passed over the threshold of her house, is commanded to undergo so long a journey of affliction, on account of this wonderful birth, and her spiritual travail.
And behold a wonder again. Palestine plots, and Egypt receives and preserves Him that is the object of the plots. For, as it appears, not only in the instance of the sons of the patriarch did types take place, but also in our Lord's own case. In many instances, we are sure, His doings at that time were prophetic declarations of what was to happen afterwards; as, for example, in the matter of the ass and the colt.
Source: Homilies on the Gospel of St. Matthew (New Advent)