Being asked by the Pharisees when the kingdom of God would come, he answered them, “The kingdom of God is not coming in ways that can be observed, nor will they say, ‘Look, here it is!’ or ‘There!’ for behold, the kingdom of God is in the midst of you.” - Luke 17:20-21 The Pharisees could not understand these words of Jesus because they did not know who Jesus was. They were expecting the Christ to be an earthly king who would restore the nation of Israel to glory. Because Jesus was clearly not this type of king, they did not recognize Him as the Christ.
Jesus rebukes their simplistic way of thinking by informing them that what they were seeking was in fact right in front of their faces. They simply did not have the eyes to see. It is important to note that the ‘kingdom of God’ is used interchangeably with ‘the kingdom of heaven’ in the four gospels. When Jesus speaks of the kingdom of God or the kingdom of heaven, He is speaking of what is simply called in modern parlance “heaven.”
Although our modern notion of ‘the Kingdom of God’ is much different from that of the Pharisees, we tend to share in their dualistic way of thinking. We think of heaven as the place we (hope to) go after we die, and earth the place we exist while we live, with an impenetrable barrier separating the two. We imagine that we have to spend our whole lives here on earth completely separate from heaven, in hopes that someday at an undisclosed point in the future we will be allowed to enter its gates.
Us moderns laugh at the Pharisees, unaware that we share in their folly. Jesus offered something far greater than what the Pharisees were able to conceive. He does the same for us.
No matter what our feeble minds, bound by the limits of space and time, are capable of conceiving, God’s Kingdom transcends it all. Jesus mentions this Kingdom dozens of times throughout the four gospels, each time revealing clues for all who are willing to accept them.
I love the Lord, because he has heard my voice and my pleas for mercy. Because he inclined his ear to me, therefore I will call on him as long as I live. - Psalm 116:1-2