What makes it such a harbinger has to do with its theme. Christ the King Sunday calls us to recognize the sovereignty of Jesus. Everything and everyone is under His sovereign power. It is a noteworthy pause as it comes as the final word of the Christian year. And, of course, what follows is the season of Advent and the early days of Advent always remind us that the One who has come will come again to establish His sovereign rule. The manger of Bethlehem may have held a baby who would save His people from their sins, but it also was filled with the King of Kings and Lord of Lords. This is the One who was worshipped by shepherds and the Kings of the East.
Just before the old year passes, Christ the King Sunday shows up on the church calendar to point us toward Jesus, the King who reigns now and forever. It is an end-of-the-year Word which causes us to realize that partial commitment will no longer cut it. Those who follow after the King who reigns sovereign above all other powers cannot appease Him with the bits and pieces of our lives. His call is for the submission of our whole self, everything we are and everything we hope to be. Anything less is less than enough.