Just as the qualities of oil and water are revealed when they are placed in the same jar, what Jesus says is clarified by two contrasting accounts in this chapter.
In the first, the disciples want the children surrounding Christ to be sent away; Jesus wants them so He can illustrate a truth: “the kingdom of God belongs to such as these. Truly I say to you, whoever does not receive the kingdom of God like a child will not enter it at all” (vv. 14b-15).
What does that mean?
We might make various suggestions. Or we can keep reading and see a contrasting story and see if it helps us understand this story.
So the rich young man comes to Jesus and boldly asserts that he is worthy of eternal life because he has fulfilled the entire second table of the Law. And then Jesus challenges him with something of an, “Oh, really?” If that is true, Jesus says, “go and sell all you possess and give to the poor, and you will have treasure in heaven; and come, follow Me” (v. 21).
And the young man went away sadly because he was very wealthy. Then Jesus concludes: “How hard it will be for those who are wealthy to enter the kingdom of God…Children, how hard it is to enter the kingdom of God!” (vv. 23-24).
The oil of the second account is placed in the beaker of water of the first account and the means of entry into God’s kingdom is clarified.
The faith of the children is contrasted with the “faith” of the rich man. The children had no treasures, no status, no authority to offer Christ. They just came to Him. The rich man, on the other hand, came trusting his accomplishments (“I’ve fulfilled the Law”) and his wealth. He came not seeking Christ, but he came essentially offering Christ something that would be of value and merit to Christ (and that Christ, he supposed, needed from him). Christ — and salvation — will not be received in that way.
How does one enter the kingdom of heaven and gain Christ and eternal life?
He receives Christ’s life by coming like a child — in humble dependence. And he receives Christ’s life by not coming like the rich young ruler — in prideful self-dependence and reliance.
The hymn writer was right:
Nothing in my hand I bring,
Simply to Thy cross I cling;
Naked, come to Thee for dress:
Helpless, look to Thee for grace.