The Solemnity of Jesus Christ, King of the Universe, recalls that Jesus is the "king of kings." However, he is not a king in the oppressive sense, but in the biblical sense, a shepherd who guards his flock.
King David, the first shepherd-king
In the Old Testament, we can see that God is slowly preparing his people for the Messiah. He changes their expectation of a king to a "shepherd-king."
David started out as a shepherd, but when he was to be made king, God continued to refer to him as a shepherd.
You shall be shepherd of my people Israel, and you shall be prince over Israel.
David is even referred to as the "one shepherd," foreshadowing the coming of Christ.
My servant David shall be king over them; and they shall all have one shepherd. They shall follow my ordinances and be careful to observe my statutes.
Even the prophets called out other kings for not being shepherds.
Your shepherds are asleep, O king of Assyria; your nobles slumber. Your people are scattered on the mountains with none to gather them.
Jesus as the Shepherd-King
The Psalms speak about God as the shepherd, looking forward to the arrival of Jesus.
Jesus himself repeatedly brought up this analogy, even calling himself the "Good Shepherd."
Scripture clearly shows that Jesus is not like earthly kings, tyrannical and distant in their behavior. Instead, Jesus is the "shepherd-king," who lays down his life for his flock, protecting it and guiding it to greener pasture.