Not sure you understand Advent? Blessed Columba will help you:
All the Old Testament is a prolonged Advent, the prayers of which are summed up in this prayer of Isaias:
Drop down dew, ye heavens, from above, and let the clouds rain the just…Let the earth be opened and bud forth a Savior!
The idea of this future Redeemer fills all the Ancient Law; all the symbols, all the rites and sacrifices prefigure Him; all desires converge toward Him. The religion of Israel was the expectation of the Messias.
But the greatness of the mystery of the Incarnation and the majesty of the Redeemer demanded that the revelation of Him to the human race should only be made by degrees…
It was by a dispensation, at once full of wisdom and mercy, that God disclosed this ineffable mystery only little by little, by the mouth of the prophets.
When the human race would be sufficiently prepared, the Word, so many times announced, so often promised, would Himself appear here below to instruct us.
(from Christ in His Mysteries)