Jesus used a child to help his self-centered disciples get the point. We are not to be childish (like the disciples, arguing over petty issues), but rather childlike, with humble and sincere hearts. Are you being childlike or childish?
Jesus called a little child to him and put the child among them. Then he said, “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. So anyone who becomes as humble as this little child is the greatest in the Kingdom of Heaven. (Matthew 18:2-4 NLT)