One of the things that make little children cute is their innocense. They have an outlook that is unencumbered by "knowledge" that so often takes the lustre off of wonderment. I recall the occasion when I was in 3rd grade that I first learned where babies come from. I, up to that point, had acquired some information about a certain behavior that "naughty" people did that was represented by a certain four letter word, but had no clue that it had anything to do with reproduction. It upset me to no end when a friend said my mom and dad had "done it" or I wouldn't have been born. I laid in bed crying that night as I considered the horrible prospect. Dad was cool in the way he helped me process that information from a biblical perspective and give it a positive, wholesome spin. Still, that passage of discovery and maturity, took away from me some of the magic and mystery about life that I had enjoyed up to the moment (though it did open the door to some enjoyable moments in my future).
I think about such milestones of learning on the journey toward adulthood when I read what Jesus said about children and his kingdom. "Jesus called a little child to Him, set him in the midst of them, and said, 'Assuredly, I say to you, unless you are converted and become as little children, you will by no means enter the kingdom of heaven. Therefore whoever humbles himself as this little child is the greatest in the kingdom of heaven.'" He made a similar point when conversing with Nicodemus as recorded in John 3. Jesus' assertion that being "born again" was the only way Nicodemus could "see the kingdom of God" was another way of saying childlikeness is essential for kingdom participation, as in the Matthew 18 passage above.
It would be equally absurd to think Jesus was requiring Nicodemus to regress to the point of going back into his mother's womb, or that I am required to delete from my understanding essential information like the facts of life before either of us can enter God's kingdom. So what was the point Jesus was making? The key phrase is humbling oneself. Jesus' disciples were keen to know the path to status in the kingdom. Jesus called a child heretofore excluded from their conversation, placed him front and center, and answered that it would be the kind of humility displayed by this child who was being asked to stand in front of a bunch of grown men that leads to greatness in God's kingdom. This child was just a little person rolling along in life not encumbered by philosophizing quests for greatness--blissfully unaware of the political scheming and self-agrandizing shenanigans that many adults get into. Much of this stuff characterizes our religious endeavors, things like striving, posturing and approval seeking.
I think Jesus was trying to get us to understand that kingdom greatness comes more readily to those who are oblivious to such things and are just happily and humbly "playing" in the playground of life.
