I think we have gotten it backwards. It's our child"ish"ness we're supposed to grow out of, not our child"like"ness! 1Corinthians 13:11 says "When I was a child, I spoke and thought and reasoned as a child. But when I grew up, I put away childish things." Matthew 18:3 has Jesus saying "I tell you the truth, unless you turn from your sins and become like little children, you will never get into the Kingdom of Heaven." Being childish is one thing but being childlike is something altogether different! Mature Christians shouldn't be selfish, silly, whiny, mischievous and the like. But neither should we forget how to have fun and enjoy the simple things in life! Children believe their fathers can fix anything and trust them implicitly. Children can play with others and never even notice the color of their skin. Children forgive and forget so easily. May we always be childlike and never childish!
" To be concerned about being grown up, to admire the grown up because it is grown up, to blush at the suspicion of being childish; these things are the marks of childhood and adolescence. And in childhood and adolescence they are, in moderation, healthy symptoms. Young things ought to want to grow. But to carry on into middle life or even into early manhood this concern about being adult is a mark of really arrested development. When I was ten, I read fairy tales in secret and would have been ashamed if I had been found doing so. Now that I am fifty I read them openly. When I became a man I put away childish things, including the fear of childishness and the desire to be very grown up." ~ CS Lewis