The Return of the King: "We live always during Advent," writes Daniélou, "we are always waiting for the Messiah to come." Jesus came once and He will come again, but He is not yet fully made known. "He is not fully manifest in mankind as a whole: that is to say, that just as Christ was born according to the flesh in Bethlehem of Judah so much he be born according to the spirit in each of our souls." Advent is anticipation, preparation, and contemplation of the King.
"Minas Tirith" is the "tower of watch". It watches the border, yes - on guard against an incursion from Mordor. It watches, too, for the return of the King. It watches for the return of life to the white tree, the return to glory for the great City of the King. And so we wait, as well. We are an advent people, just like the people of Gondor. Like them, we cannot watch complacently. We cannot watch idly not just because the forces of darkness are close but because we do not know when our King will return. So we wait faithfully and keep watch in hope. We wait in "anticipation, preparation, and contemplation of the King."