Blessing of the Children

The disciples would have thrust them away, from respect to Christ's dignity. But the Lord teaching them holy thoughts, and to subdue the pride of this world, took the children into His arms, and promised to such the kingdom of heaven; But Jesus said to them, "Suffer little children and forbid them not to come to me, for of such is the kingdom of heaven." For who were worthy to come to Christ, if simple children were thrust away? Therefore he said, "Forbid them not." For if they shall turn out saints, why do you hinder the sons from coming to their Father? And if sinners, why do you pronounce a sentence of condemnation, before you see any fault in them? He said distinctly, "Of such is the kingdom of heaven", not of these, to show that it was not age, but disposition that determined His judgment, and that the reward was promised to such that had child-like innocence and simplicity.

This passage instructs all parents to bring their children to the priests, for it is not the priest who lays his hands on them, but Christ, in whose name hands are laid. For if he that offers his food in prayer to God eats it sanctified, for it is sanctified by the word of God, and by prayer, as the Apostle speaks, how much rather should children be offered to God, and sanctified?

Reference:
Catena Aurea (St. Thomas Aquinas)
Opus imperfectum in Mattheum (Pseudo-Chrysostom)
Commentariorum In Evangelium Matthaei (St. Jerome)
Homily 62 on Matthew (St. John Chrysostom)
St. Remigius of Auxerre
Origen