Matthew 13:31-35
31 He put before them another parable: “The kingdom of heaven is like a mustard seed that someone took and sowed in his field; 32 it is the smallest of all the seeds, but when it has grown it is the greatest of shrubs and becomes a tree, so that the birds of the air come and make nests in its branches.”
33 He told them another parable: “The kingdom of heaven is like yeast that a woman took and mixed in with three measures of flour until all of it was leavened.”
34 Jesus told the crowds all these things in parables; without a parable he told them nothing. 35 This was to fulfill what had been spoken through the prophet:

“I will open my mouth to speak in parables;
I will proclaim what has been hidden from the foundation of the world.”

From the New Revised Standard Version. Reprinted with permission from HarperBibles.