In Luke 13, Jesus describes the kingdom of God to a tree that grows from a very small mustard seed. When it grows, it's big enough for birds to perch in the branches! It's also like a tiny grain of yeast. Although it's small, when it gets put into warm water it multiplies. It grows so fast that it can puff up sixty pounds of flour. The kingdom of God may start small, but it spreads and gradually changes into something that has the power to change things.