What then does it mean to say that one cannot enter the Dominion unless one receives the Dominion here and now as a child? I suspect that in the first place, Jesus had in mind the fact that children have no difficulty receiving gifts. Indeed, nearly everything children receive comes as a gift, not as something they have earned. Have you ever noticed how at Christmas children have no difficulty receiving gifts, without immediately wondering who they must repay?
An adult, on the other hand, often has difficulty or feels uncomfortable with receiving a gift from someone he or she has not also given a gift to. Why is this? I suspect it is in part because our society tells us repeatedly “you don’t get something for nothing” or “you get what you earn or pay for.” Our culture is fundamentally works-oriented, not grace-centered. We like to think of ourselves as those who need no help, but rather, given an opportunity, can get it for ourselves. We like to be independent. A child, on the other hand, knows very well that he or she is dependent on others. Children are under no delusion that they have all that they get because they have or must have earned it or that it comes as part of some sort of gift exchange, some sort of “you scratch my back, I’ll scratch yours” reciprocity ritual. They know how to receive, and this includes knowing how to receive the Dominion, the saving rule of God in one’s life.
Ben Witherington in Imminent Domain: The Story of the Kingdom of God and Its Celebration (p.33)