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 ESV)
"Now they were bringing even infants to him that he might touch them." (Luke 18:15 ESV)
At the turn of the previous century, B. B. Warfield, Professor of Systematic Theology at Princeton, would give Sunday afternoon sermons to the students on campus. A number of these have been collected and published in Faith and Life (Banner of Truth, 1974).
In this message on Jesus' blessing of the children (from Mark 10 and Luke 18) Warfield sought to understand just what it was about children (many of them infants) that made them suitable examples for entry into God's Kingdom. He ruled out innocence, since human depravity runs deep in our nature, even from before birth. He ruled out humility and simplicity, since children early manifest a high degree of selfishness, and infants really aren't capable of choosing to be humble.
The excerpts that follow are Warfield's explanation of what receiving the kingdom like a child means...
"The particular trait which our Saviour has in mind when He declares that only the childlike can enter His Kingdom is the trustfulness of the child. Here we touch, indeed, what seems really the fundamental trait of the truly childish mind, that colors all its moral life, and constitutes, not merely its dominant but we might almost say, its entire disposition— implicit trustfulness. The age of childhood is, above everything else, the age of trust. Dependent upon its elders for everything, the whole nature of the child is keyed to trust; on trust it lives, and by means of trust it finds all its means of existence. Its virtues and its faults alike grow out of trust as its fundamental characteristic. There is no picture of perfect and simple and implicit trust discoverable in all the world comparable to the picture of the infant lying peacefully and serenely on its mother's bosom.
"They lay happy and thoughtless in their mother’s arms and in Jesus’ own arms. Their characteristic was just helpless dependence; complete dependence upon the care of those whose care for them was necessary.
"And it would seem that it is just this objective helpless dependence which is the point of comparison between them and the children of the Kingdom.
"Trust, simple, utter trust, that is the pathway to the Kingdom.
"The Kingdom of God is not taken – acquired – laid hold of; it is just 'received.' It comes to men, men do not come to it.
"It is purely a gift, a gift of God’s; and they who receive it must receive it purely as a gift. He who will not humble himself and enter it as a little child enters the world, in utter nakedness and complete dependence, shall never see it."
You can read this sermon online here.