Luke 17:20 And when he was demanded of the Pharisees, when the kingdom of God should come, he answered them and said, The kingdom of God cometh not with observation:
Jesus was speaking of the spiritual kingdom of God that was even there before the Pharisees in the presence of Jesus. Jesus is the kingdom on earth at that time. They were proud and thought they knew scriptures, but they did not see nor believe the kingdom manifest through Jesus.
Luke 17:21 Neither shall they say, Lo here! or, lo there! for, behold, the kingdom of God is within you.
The kingdom was not to be seen outwardly, but within a born-again believer.
John 3:3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
John 3:5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.
John 3:6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
John 3:7 Marvel not that I said unto thee, Ye must be born again.
John 3:8 The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit.
Born of water after the natural birth. Going through the water of repentance and being baptized in the baptism of Jesus, in the Holy Spirit.
John 18:36 Jesus answered(to Pilate), My kingdom is not of this world: if my kingdom were of this world, then would my servants fight, that I should not be delivered to the Jews: but now is my kingdom not from hence.
John 18:37 Pilate therefore said unto him, Art thou a king then? Jesus answered,
Thou sayest that I am a king. To this end was I born, and for this cause came I into the world, that I should bear witness unto the truth. Every one that is of the truth heareth my voice.