Matthew 13:31-33

Another story by way of comparison He set forth before them, saying, The kingdom of heaven is like a grain of mustard seed, which a man took and sowed in his field. Of all the seeds it is the smallest, but when it has grown it is the largest of the garden herbs and becomes a tree, so that the birds of the air come and find shelter in its branches. He told them another parable: The kingdom of heaven is like leaven (sour dough) which a woman took and covered over in three measures of meal or flour till all of it was leavened. [Gen. 18:6.]