Jesus told them another parable. He said:
To what can we compare the kingdom of God? What parable can explain its excellence?
The kingdom of heaven is like a grain of mustard seed, which a man took and planted in his field. A mustard seed is the smallest of seeds grown in the garden.
But once it starts growing, it gets bigger and bigger, bigger than any of the other plants in the garden. Finally, it grows to the size of a tree and puts out large branches.
The birds come and take refuge and find shade and make their homes in its branches.
In another parable, Jesus said that the kingdom of heaven is like the yeast that a woman hid in three measures of flour, and it was mixed into and permeated all of the dough.
Jesus told all these parables to the multitudes, and he only taught them in parables with no explanation. This was a fulfillment of the prophecies found in the Psalms that said:
I will open my mouth in parable; I will say things hidden since the foundation of the world.
But to his own disciples he explained everything.