Just before this verse the disciples are talking with each other and then ask Jesus who is the greatest in heaven. I have a feeling they arguing about who was the best and who would be the greatest of them in heaven and Jesus totally shuts them down and points out the faith of the little ones around him. Child like faith is difficult as the years grow on us but Jesus shows us here that is the most rewarding way to experience Him. We can learn a lot from how much children must rely on their parents and we too can be like that to Jesus no matter how old we get.