Adam Clarke's Commentary on the Bible

Verse 13 (Matthew 19:13)

Then were there brought unto him little children - These are termed by Luke, Luke 18:15 , τα βρεφη , infants, very young children; and it was on this account, probably, that the disciples rebuked the parents, thinking them too young to receive good. See on Mark 10:16 ; (note).

That he should put his hands - It was a common custom among the Jews to lay their hands on the heads of those whom they blessed, or for whom they prayed. This seems to have been done by way of dedication or consecration to God - the person being considered as the sacred property of God ever after. Often God added a testimony of his approbation, by communicating some extraordinary influence of the Holy Spirit. This rite has been long practised among Christians, when persons are appointed to any sacred office. But this consecration of children to God seems to have grown out of use. It is no wonder that the great mass of children are so wicked, when so few, are put under the care of Christ by humble, praying, believing parents. Let every parent that fears God bring up his children in that fear; and, by baptism, let each be dedicated to the holy trinity. Whatever is solemnly consecrated to God abides under his protection and blessing.

- Adam Clarke's Commentary on the Bible