He said that only those with a childlike attitude, one of faith and trust, are able to be a part of it. God's kingdom is different. But Jesus described God's kingdom as a great banquet with folks coming from North and South, East and West. This kingdom is universal with no boundaries at all. God's kingdom is different.
Earthly kingdoms are very careful about who is acceptable as a member of society.
But Jesus described God's kingdom as a large tree in a garden with branches so extensive that all sorts of birds will be able to nest in it. THIS kingdom is open to all who, by faith, would become a part of it. First-class citizenship is graciously offered to anyone who wants it. God's kingdom is different. The writer of our lesson in Revelation understood that.