Grace and Space

Mt 18:1-5, 10
Child: In ancient patriarchal societies like that of the Jews, a newborn child could easily be abandoned—to slavery at best, to death at worst—if the father did not lift it into his arms and declare it was to live as his child. Maternal birth made a child a nobody; paternal acceptance made the child a somebody. Children in first-century Israel have no legal personalities and like women count for nothing.
Classical romanticism would ascribe to the child an image of innocence, simplicity, and humility. The metaphor used by Jesus does not suggest any of these. Instead, the child is the paradigm of being a nobody. Thus, when Jesus presents the child as the greatest in the kingdom of heaven, he is saying, in effect, that a nobody is the greatest.
Put simply, in the coming reign of God, nobody can lay claim to the position of being the greatest. For the kingdom of God is radically egalitarian in nature; there is no high or low position. Worldly standards do not apply to the kingdom.
What is true for us now as regards a worldly hierarchy and the corresponding system of promotion and achievements does not apply in the world to come. All humans are equal; God alone is above all, that is why he is the only king. Entrance to his kingdom is neither merited nor achieved. It is freely given out of his generosity and magnanimity.