Jesus spoke many parables about the kingdom of God.
See Matthew Chapter 13
Luke Chapter 13: 18-20
“The kingdom of God does not come with your careful
observation, 21 nor will people say, ‘Here it is,’ or
‘There it is,’ because the kingdom of God is within you.”
(Luke 17: 20)
“Let the little children come to me, and do not hinder
them, for the kingdom of God belongs to such as these.
I tell you the truth, anyone who will not receive the
kingdom of God like a little child will never enter it.”
(Luke 18: 16-17)
“I tell you the truth, no one can see the kingdom of God
unless he is born again. Flesh gives birth to flesh,
but the Spirit gives birth to spirit. You should not be
surprised at my saying, ‘You must be born again.
(John 3: 3. 6)