Flatten the mountains and hills. Straighten the roads. Fill in the potholes. The Lord is coming to bring salvation. Stir up our hearts, O Lord, to make ready the way of your only-begotten Son that at His second coming we may worship him in purity.
Advent is a time for preparation.
It's a time to prepare for the glorious feast of Christmas, and the coming of Christ in humility. It's also a time to prepare for the glorious feast of the Last Day, and the coming of Christ in glory. We know precisely how many days until Christmas. Eighteen and counting. We don't know how many days until the Last Day, however.