In the NT 'The Kingdom of God' has two principal meanings.
One meaning considers that the Kingdom of God already exists, being
the faithful as a group, or their faith itself seen as an entity.
Matthew 12:28 But if it is by the Spirit of God that I cast out demons, then the kingdom of God has come upon you.
Mark 4:26 And he said, "The kingdom of God is as if a man should scatter seed upon the ground,
Mark 10:15 Truly, I say to you, whoever does not receive the kingdom of God like a child shall not enter it."
Luke 10:9 heal the sick in it and say to them, 'The kingdom of God has come near to you.'
Luke 10:11 'Even the dust of your town that clings to our feet, we wipe off against you; nevertheless know this, that the kingdom of God has come near.'
Luke 11:20 But if it is by the finger of God that I cast out demons, then the kingdom of God has come upon you.
Luke 17:20 Being asked by the Pharisees when the kingdom of God was coming, he answered them, "The kingdom of God is not coming with signs to be observed;
1 Luke 17:21 nor will they say, 'Lo, here it is!' or 'There!' for behold, the kingdom of God is in the midst of you."
1 Romans 14:17 For the kingdom of God is not food and drink but righteousness and peace and joy in the Holy Spirit;
The other meaning refers to
a future state, perhaps on earth, perhaps in Heaven.
Mark 1:15 and saying, "The time is fulfilled, and the kingdom of God is at hand; repent, and believe in the gospel."
Mark 9:1 And he said to them, "Truly, I say to you, there are some standing here who will not taste death before they see that the kingdom of God has come with power."
Mark 9:47 And if your eye causes you to sin, pluck it out; it is better for you to enter the kingdom of God with one eye than with two eyes to be thrown into hell,
Mark 10:23 And Jesus looked around and said to his disciples, "How hard it will be for those who have riches to enter the kingdom of God!"
Mark 10:24 And the disciples were amazed at his words. But Jesus said to them again, "Children, how hard it is to enter the kingdom of God!
Mark 14:25 Truly, I say to you, I shall not drink again of the fruit of the vine until that day when I drink it new in the kingdom of God."
Matthew 21:31 “Which of the two did the will of his father?" They said, "The first." Jesus said to them, "Truly, I say to you, the tax collectors and the harlots go into the kingdom of God before you.
Luke 7:28 I tell you, among those born of women none is greater than John; yet he who is least in the kingdom of God is greater than he."
Luke 9:27 But I tell you truly, there are some standing here who will not taste death before they see the kingdom of God."
Luke 13:28 There you will weep and gnash your teeth, when you see Abraham and Isaac and Jacob and all the prophets in the kingdom of God and you yourselves thrust out.
Luke 21:31 So also, when you see these things taking place, you know that the kingdom of God is near.
Luke 22:16 for I tell you I shall not eat it until it is fulfilled in the kingdom of God."
Luke 22:18 for I tell you that from now on I shall not drink of the fruit of the vine until the kingdom of God comes."
and outside the gospels:
Acts 1:3 To them he presented himself alive after his passion by many proofs, appearing to them during forty days, and speaking of the kingdom of God.
Acts 14:22 strengthening the souls of the disciples, exhorting them to continue in the faith, and saying that through many tribulations we must enter the kingdom of God.
1 Corinthians 6:9 Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither the immoral, nor idolaters, nor adulterers, nor sexual perverts,
1 Corinthians 6:10 nor thieves, nor the greedy, nor drunkards, nor revilers, nor robbers will inherit the kingdom of God.
1 Corinthians 15:50 I tell you this, brethren: flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable.
Galatians 5:21 envy, drunkenness, carousing, and the like. I warn you, as I warned you before, that those who do such things shall not inherit the kingdom of God.
2 Thessalonians 1:5 This is evidence of the righteous judgment of God, that you may be made worthy of the kingdom of God, for which you are suffering─
And there's a further 36 verses that use the phrase but could be read either way.