When we say Jesus is a king, we mean a few things. First, He is our Shepherd. As our Shepherd He desires to lead us personally as a loving father would. He wants to enter our lives personally, intimately and carefully, never imposing Himself but always offering Himself as our guide. The difficulty with this is that it’s very easy for us to reject this kind of kingship. As King, Jesus desires to lead every aspect of our lives and lead us in all things. He desires to become the absolute ruler and monarch of our souls. He wants us to come to Him for everything and to become dependent upon Him always. But He will not impose this sort of kingship upon us. We must accept it freely and without reservation. Jesus will only govern our lives if we freely surrender ourselves over. When that happens, though, His Kingdom begins to become established within us! And through us in the world.
Additionally, Jesus does wish for His Kingdom to begin to be established in our world. First and foremost this takes place when we become His sheep and thus become His instruments to help convert the world. However, as King, He also calls us to establish His Kingdom by seeing to it that His truth and law is respected within civil society. It’s Christ’s authority as King that gives us the authority and duty as Christians to do all we can to fight civil injustices and bring about a respect for every human person. All civil law ultimately gains its authority from Christ alone since He is the one and only Universal King.