People often claim that when Jesus said, “My kingdom is not of this world..." (John 18:36) he was emphasizing the heavenly, non-earthly nature of his kingdom, which, historically, has also led many Christians to disconnect the land of Israel, and even the entire physical earth, from their eschatology.
What these people miss, however, is that the Greek word for world (kosmos) can have either a geographical/territorial meaning or a qualitative/ethical meaning in the NT.
For example, when Paul says that God made the world (kosmos) (Acts 17:24), he is using kosmos in a basic, geographical sense to refer to the material world.
On the other hand, when Paul says, "The wisdom of this world is foolishness" (1 Cor. 3:19), he is not saying that the mountains and the oceans are stupid.
He is saying that the values, ways of thinking, and qualities of people in this world do not bring them to an understanding of the Gospel.
That's the second way the NT authors will often use the word kosmos.
Again, the usage there is more qualitative and figurative, not geographical.
So when Jesus says, "My kingdom is not of this world" (Jn. 18:36), he is not saying that his kingdom will never be established on this earth, nor is he saying that his kingdom will never be established in Israel, because we know that's not true (see Luke 1:32, for example, where Gabriel says Jesus will inherit "the throne of his father David," which is in Jerusalem, not in heaven."
The point of John 18:36 is simply that Jesus' kingdom was not going to be instituted through worldly means.
This is why he follows up by saying:
"If My kingdom were of this world, then My servants would be fighting so that I would not be handed over to the Jews." (Jn. 18:36b)
All Jesus is saying here is that his kingdom was not dependent upon his followers engaging in worldly violence to stop him from being crucified.
His kingdom was going to advance in spite of his crucifixion, and in reality, because of it.
Notice the direct connection in the context between "this world" and "fighting."
Thus, in no way does John 18:36 provide a repudiation of the first-century, Jewish expectation that the Messiah would reign *on this earth, from Jerusalem.*
Jesus is simply saying here that his kingdom would come first through his suffering, as well as through the suffering of his followers.
This entire statement needs to be understood as an explanation of why Jesus was submitting to crucifixion at that time.
And, just as a sidenote, this verse also does not justify total Christian pacifism in the face of evil, and it also doesn't cancel out the idea that Jesus will return as a man of war at the time of his second coming (see. Rev. 19:11).
Again, Jesus is not giving us a comprehensive political philosophy here, and nor is he giving us a comprehensive eschatology as it relates to what he will do when he returns.
He is simply saying, "My kingdom must advance through my suffering first, not through my disciples taking up arms in an attempt to violently stop my crucifixion."
Now, of course, there are applications of this statement for us in the modern day as well.
Maybe we can glean from this verse that as much as we should try not to lose in the political sphere, we shouldn't try to win at the expense of following Jesus, or at the expense of picking up our cross.
Furthermore, as much as we should not become self-appointed martyrs, and as much as we should hope that the people who hold governmental power are either Christians or at least friendly to Christians, and therefore willing to implement Christ-honoring policies, maybe John 18:36 is there to remind us that sometimes, the people of God simply cannot avoid losing and suffering in this world, and that when we do, God is still in control and His kingdom is still advancing nonetheless.
Indeed, the Messianic kingdom is not of this world.
It is not dependent upon us engaging in every worldly methodology to only win and never lose, or to only triumph and never suffer.
Rather, the Messianic kingdom is solely dependent on the crucified Son of Man who went to the cross so that he can return with a sword.
His kingdom was inevitable even in the face of his suffering, defeat, and loss, and it is inevitable even when we experience the same. - Travis M. Snow