Jesus used two figures of speech to demonstrate the internal and external growth of the Kingdom of God. Jesus first compared the Kingdom to a mustard seed. A mustard seed is a very small seed that when planted rapidly develops into a garden plant with tree-like proportions—large enough for birds to perch on its branches (vs. 19). Jesus then compares the Kingdom to yeast that is mixed into dough and causes the dough to rise (vs 21). While the mustard seed comparison indicates external growth or expansion, the yeast comparison indicates internal growth through permeation or infusion. The Kingdom of God infiltrates and pervades this world like yeast and grows and expands like a mustard tree. According to Jesus, God's Kingdom expands within our individual and collective lives in the same way that the mustard seed grows and the yeast permeates. The Kingdom of God is a living organism whose nature is one of dynamic growth and continual reproduction. God's Kingdom cannot remain static--it wants to grow both within you and in this world.
