What does the author say Jesus' parable about mustard seeds implicate?

The author discusses the contemporary implications of Jesus' famous parable about the Kingdom of God being like the mustard seed. In the time and place in which the parable was recounted, the author writes, mustard was a dangerous, invasive plant that could take over a garden or field. Therefore it is likely Jesus is suggesting the Kingdom is so powerful it could invade spheres of power and control dominated by others.