Matthew 18:3

And said, “Truly, I say to you, unless you turn and become like children, you will never enter the kingdom of heaven.

Matthew 19:14

But Jesus said, “Let the little children come to me and do not hinder them, for to such belongs the kingdom of heaven.”

Luke 18:17

Truly, I say to you, whoever does not receive the kingdom of God like a child shall not enter it.”