“Truly I tell you, anyone who will not receive the kingdom of God like a little child will never enter it.” – Jesus, Matthew 10:15
Heaven is inhabited and the earth inherited by 10-year-olds.
They are not all physically 10 but have shook hands and embraced their former 10 year old selves. It’s what is meant by those who talk about the inner child. And it’s more than an ego state.
Paul spoke of mortifying the flesh (Rom 8:13) — killing off the old man. It is in doing away with the old tyrant who only worries about money, status, power and popularity.
Entering the kingdom of God as a child is a resurrection of that 10-year-old who believed in love, farts, pizza and standing up for a friend. These were the only thing a person needed to exist back then and the wise know nothing ever changed.