The parables of Jesus have been consistently misinterpreted. Take for example, the parables of the mustard seed and the yeast, for which Jesus gives no explanation:
The kingdom of heaven is like a mustard seed that a man takes and sows in his field. It is the smallest of all seeds, but when it is grown, it is the greatest among herbs, and becomes a tree, and the birds come and roost in its branches.
The kingdom of heaven is like the yeast that a woman takes and mixes in three measures of meal, until the whole is leavened.
These parables have been widely interpreted to be a prophesy of the church. But Jesus rarely spoke about building a church. He is consistent in speaking of the kingdom of heaven as the future utopian kingdom of earth, to be ushered in by the Son of Man, the cosmic judge predicted by the prophet Daniel, and Jesus thought that it would arrive during the lifetimes of some of his disciples.
So what do these parables really mean? In the first, the kingdom is compared to a tiny thing which grows into something big that gives shelter. In the other, a small thing is mixed into a larger thing, and causes the whole to rise. I believe that Jesus is talking about his movement, those who are ready for the coming kingdom of heaven, growing until the kingdom becomes a reality, and how the movement will accomplish this by causing the rest of society to rise to the same level.