Philip Yancey, in What’s so Amazing about Grace?
Jesus’ images portray the kingdom as a kind of secret force. Sheep among wolves, treasure hidden in a field, the tiniest seed in the garden, wheat growing among weeds, a pinch of yeast worked into bread dough, a sprinkling of sale on meat–all these hint at a movement that works within society, changing it from the inside out. You do not need a shovelful of salt to preserve a slab of ham; a dusting will suffice.
Jesus did not leave an organized host of followers, for he knew that a handful of salt would gradually work its way through the mightiest empire in the world. Against all odds, the great institutions of Rome–the law code, libraries, the Senate, Roman legions, roads, aqueducts, public monuments–gradually crumbled, but the little band to whom Jesus gave these images prevailed and continues on today.