Jesus said: "The kingdom of God is among you", Luke 17:21. This means that the kingdom has a double meaning: is inside and outside of you. The kingdom of God is the dominion of the qualities of God, the dominion of the mercy, the dominion of the perseverance, the empire of the joy, the reign of the peace. The qualities of God are perfections, that means that the kingdom of God is the culture of the excellence.
The kingdom is not the church as many authors expresses, remember the parables, the parables tell us about growth (parable of the yeast Matthew 13:33), transformation (parable of the Mustard seed Matthew 13:31-32), and inner search (parable of the hidden treasure, Matthew 13:44).
The kingdom is an ethical concept. To say that spiritual gifts are perfections is to say that all the spiritual gifts are Good. God is the source of the good.
The kingdom within you is to live the spiritual gifts we inherit from God, to live according to the spirit, that is to search the correct and the best, the correct for the spiritual gift of counsel and the best for the piety, the mercy. To live the spiritual gifts is also to be progressive (way), precise and exact (truth) and increase the life, "I am the way, the truth and the life" John 14:6.
The greek concepts like justice and prudence not belong to the teachings of the kingdom because justice and prudence are not perfections, not all justice is good, not all prudence is correct. The justice as concept or virtue is an heresy (teaching of the error) that get us away from the path of mercy, the path of perseverance, of piety