Scripture holds up being childlike, not childish. The disciples are behaving like children here, but in all the wrong ways. Mark tells us that the disciples had been arguing about who was the greatest, and that they were reluctant to tell Jesus what the issue was. I’m sure if we had a transcript it would read as follows:
“Oh, yeah well…”
There is a way we should be like children, but it should lead to us growing up. “Like newborn infants, long for the pure spiritual milk, that by it you may grow up into salvation (1 Peter 2:2).” In Ephesians 4:12-13 Paul tells us that Jesus gifts His church with shepherds “to equip the saints for the work of ministry, for building up the body of Christ, until we all attain to the unity of the faith and of the knowledge of the Son of God, to mature manhood, to the measure of the stature of the fullness of Christ.” There is a way in which the child of God should be childlike, but the result should be not a resembling of Benjamin Button, but of Jesus Christ.
Jesus says we must become like a child to even enter the kingdom, and then He says that the greatest only go deeper in this childlikeness. In what way are we to be childlike? Note that we are to humble ourselves to become like a child, we are not told to be humble like a child. Children can be as pompous as an adult. The humbling is in becoming like a child. In a sermon on Mark 10:13-16, B.B. Warfield says, “Childlikeness is one thing; that by which the state is attained is another.” Humility is a road, but a road to where? Warfield deals with the various options, arguing against simplicity, trustfulness, innocence, and humility. Ultimately taking his cues from Mark 10:15 he argues for dependence; “Truly I say to you, whoever does not receive the kingdom of God like a child cannot enter it.” The kingdom is to be received, and that like a child. The childlikeness we are to have is in relation to our receiving.
Children are altogether dependent on another. This is why it is so humbling to become one. Kingdom greatness isn’t achieved by the ambitiously accomplished, but the desperately dependent. Cool big varsity kids won’t get to play the kingdom game. They won’t even ride the pine. They will be thrown into outer darkness. The kingdom is for “little ones”. And the greatest, go deep in their dependence.
Because of the fall, man is a vacuum in a dirty world. He can only suck in dirt. Thus his desperation. If man is to be “converted” from a vacuum to a water hose, dispensing water instead of sucking dirt, the water must come from an outside source. Thus his dependance. The greatest, those who disperse the most water, are the biggest consumers of grace. They pump out what they are chugging down. They know the true of the vine taught in John 15, that it is by abiding in Christ that they bear much fruit. They humbly admit any greatness they posses is not their own, but Christ’s.