Glossa Ordinaria
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.
While His adversaries were ashamed, and the people rejoiced, at the glorious things that were done by Christ, He proceeds to explain the progress of the Gospel under certain similitudes, as it follows, Then said he, Unto what is the kingdom of God like? It is like a grain of mustard seed, &c. (Mat. 17:19.)