Ambrose of Milan
Catena Aurea · Lukasevangelium 13
Then said he, Unto what is the kingdom of God like? and whereunto shall I resemble it? It is like a grain of mustard seed, which a man took, and cast into his garden; and it grew, and waxed a great tree; and the fowls of the air lodged in the branches of it. And again he said, Whereunto shall I liken the kingdom of God? It is like leaven, which a woman took and hid in three measures of meal, till the whole was leavened. He next likens the kingdom of God to leaven, for it follows, And again he says, Whereunto shall I liken it? It is like to leaven, &c.
Many think Christ is the leaven, for leaven which is made from meal, excels its kind in strength, not in appearance. So also Christ (according to the Fathers) shone forth above others equal in body, but unapproachable in excellence. The Holy Church therefore represents the type of the woman, of whom it is added, Which a woman, took and hid in three measures (sata) of meal, till the whole was leavened.