Matthew 13:33

ὁμοία … ζύμῃ, like in respect of pervasive influence. In Rabbinical theology leaven was used as an emblem of evil desire (Weber, p. 221). Jesus had the courage to use it as an emblem of the best thing in the world, the Kingdom of God coming into the heart of the individual and the community. ἐνέκρυψεν, hid by the process of kneading. ἔως οὒ ἐζυμώθη : ἔως with the indicative, referring to an actual past occurrence.

Both these parables show how thoroughly Jesus was aware that great things grow from minute beginnings. How different His idea of the coming of the kingdom, from the current one of a glorious, mighty empire coming suddenly, full grown! Instead of that a mustard seed, a little leaven!