"What did Jesus mean by ‘the kingdom of God is within you’ in Luke 17:21?"

In Luke 17:21, Jesus says, "Nor will they say, ‘Look, here it is!’ or ‘There it is!’ For behold, the kingdom of God is within you.”

I’ve heard different interpretations of this verse. Some say it means the kingdom of God is a spiritual reality within believers, while others suggest it refers to Jesus’ presence among the people.

Does this verse mean the kingdom is something internal and personal, or is it about God’s reign in the world? How should we understand this in the broader context of Jesus’ teachings?