Luke 18:17

I assure you and most solemnly say to you, whoever does not receive the kingdom of God [with faith and humility] like a child will not enter it at all.”

Mark 10:15

I assure you and most solemnly say to you, whoever does not receive and welcome the kingdom of God like a child will not enter it at all.”

Psalm 131:1-2

Lord, my heart is not proud, nor my eyes haughty;
Nor do I involve myself in great matters,
Or in things too difficult for me.

and said, “I assure you and most solemnly say to you, unless you repent [that is, change your inner self—your old way of thinking, live changed lives] and become like children [trusting, humble, and forgiving], you will never enter the kingdom of heaven.

1 Peter 1:14

[Live] as obedient children [of God]; do not be conformed to the evil desires which governed you in your ignorance [before you knew the requirements and transforming power of the good news regarding salvation].