And he said: “Truly I tell you, unless you change and become like little children, you will never enter the kingdom of heaven. Therefore, whoever takes the lowly position of this child is the greatest in the kingdom of heaven.  And whoever welcomes one such child in my name welcomes me. Matthew 18:3-5

“See that you do not despise one of these little ones. For I tell you that in heaven their angels always see the face of my Father who is in heaven.” Matthew 18:10

And he said to his disciples, “Temptations to sin are sure to come, but woe to the one through whom they come! It would be better for him if a millstone were hung around his neck and he were cast into the sea than that he should cause one of these little ones to sin. Luke 17:1-2

Train up a child in the way he should go; even when he is old he will not depart from it. Proverbs 22:6