Belonging to the kingdom of Christ means you know the kingdom has come. In Matthew 12:28, Jesus said, “If I drive out demons by the Spirit of God, then the kingdom of God has come upon you.” He said similar things when he healed people and showed his authority. That is the whole point of the miraculous earthly ministry of Jesus. He was proving that God had come into the world in a new and powerful way. Satan would be bound like a dog on a short leash. Death would no longer have the power of fear in human hearts. Because the king had come, his kingdom had come. In Luke 17:21, the Pharisees ask Jesus when the kingdom of God would come. Jesus replied, “The kingdom of God does not come with your careful observation, nor will people say, ‘Here it is, or there it is,’ because the kingdom of God is within [or among] you.” This was a radical statement. When everybody looked forward to the day when God would fix everything, set up his kingdom in a specific nation, and sort out the good guys and the bad guys once and for all, Jesus said, take a look, and you will see that God’s reigning power is right here among you, because I am among you.
Belonging to the kingdom of Christ also means you have a different source of life. In John 3:5 Jesus said, “No one can enter the kingdom of God unless he is born of water and the Spirit. You must be born again.” Living in the kingdom of Christ means that you have a different way of life because you have a different source of life. Your spiritual birth means that your heart longs for what God loves, your emotions respond to things that are good and right, and your mind is awakened to what God is doing and sharpened by the specific teachings that come through his word. You’re alive to God and alive to the world around you. When you see kingdoms in conflict your heart breaks because you know that if everybody was born into and lived under the goodness and authority of the kingdom of Christ, life would be different.