"And they were bringing children to him that he might touch them, and the disciples rebuked them. But when Jesus saw it, he was indignant and said to them, 'Let the children come to me; do not hinder them, for to such belongs the kingdom of God. Truly, I say to you, whoever does not receive the kingdom of God like a child shall not enter it.' And he took them in his arms and blessed them, laying his hands on them." Mark 10:13-16
"If the disciples thought children too small or too unimportant for the serious work of the kingdom, they were wrong. Jesus welcomes children, takes them in his arms and declares that of such is the kingdom of heaven. The force of his words is clear. He does not say merely that the kingdom of heaven is for the childlike. He says that the kingdom belongs to them; it is made up of children and of those who come as children."
Edmund P. Clowney, The Church, page 283.