In the Gospels, for instance, we sometimes find the kingdom of heaven illustrated by principles drawn from observation of this world rather than from an ideal conception of justice; ... They remind us that the God we are seeking is present and active, that he is the living God; they are doubtless necessary if we are to keep religion from passing into a mere idealism and God into the vanishing point of our thought and endeavour.
"Interpretations of Poetry and Religion" by George Santayana, (p. 54), 1900.