What is the significance of Jesus as the King of Israel?

In the Gospel of John, when Nathanael acknowledges Jesus as the King of Israel, it underscores Jesus' fulfillment of Old Testament prophecies regarding the Messiah. His kingship is not merely political but points to His divine authority as the Savior who comes to redeem His people. This belief reflects the Reformed understanding that Jesus' mission was predetermined by God, as He serves as the ultimate Mediator who reconciles humanity while fulfilling God's covenant promises, illustrating the depth of God's grace through Christ.