Matthew 18:2-4

He called a little child and set him before them, 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. Therefore, whoever humbles himself like this child is greatest in the kingdom of heaven.