The difficulty of this verse is that it appears to contradict other scriptures of the New Testament that show the kingdom of God to be something that would be established in this world. Adding to the apparent confusion, Jesus said in the second half of John 18:36 that his kingdom was not “in,” but “from” another place.
The answer to the seeming difficulty is that both aspects of the kingdom of God are true. On the one hand, the kingdom of God is certainly in heaven. This seems obvious in the expression “the kingdom of heaven,” though that is actually not a proof. Matthew, writing to a predominantly Jewish audience, used “kingdom of heaven” because many Jews used that expression in order to avoid unnecessary use of the name of God – just as in English people sometimes say “Good heavens,” which is just an indirect way of using God’s name. All the other Gospel writers use “kingdom of God.” But apart from this detail it is obvious that God rules as King in heaven and in that sense, the “kingdom of God” is the “kingdom of heaven” (see Matthew 5:34; Daniel 4:37; etc.).
On the other hand, a great many scriptures clearly show the kingdom of heaven will be established on earth – something Christ said we should pray for (Matthew 6:10) and a truth at the core of his teaching, as we see in the Gospels: “Repent, for the kingdom of heaven has come near” (Matthew 3:2). The situation is not unlike that of earlier centuries when the colonial powers were located in their own countries, but took over distant lands. It was equally true to say that the “kingdom of France” and the “kingdom of England” were in their respective areas, but also that these kingdoms were “coming near” the areas they annexed, and that the rule of those kingdoms was finally established in the new lands.
With this background and a little extra information, we can now understand the meaning of Jesus’ words in John 18.36. The Greek word used in John (basileia) and translated “kingdom” can mean not only the physical actual kingdom, but also the “rule” or “authority” of the king. In that sense, it is like the colonial analogy we used. French Canada, called “New France,” was not France, but part of the kingdom of France in the sense it was under the rule of the king of France. Sometimes people say that Christ did not speak Greek, but rather would have said these words in Aramaic or possibly Hebrew. Even if that is true, the Aramaic (malkuta) and Hebrew (malkuth) words have exactly the same double meaning.
So, the words “My kingdom is not of this world” spoken by Jesus can just as properly be translated “My authority is not of this world … my authority is from another place.” Jesus’ words do not refer then to being the ruler of the kingdom in heaven, but to his having authority from the kingdom in heaven.
When we understand the double meaning of “kingdom,” we can see how John 18:36 does not contradict the many scriptures regarding the establishment of the kingdom of God on earth, but simply refers to the origin of Christ’s authority as that kingdom’s King.