Bede the Venerable
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.
Now the man, is Christ, the garden, His Church, to be cultivated by His discipline. He is well said to have taken the grain, because the gifts which He together with the Father gave to us from His divinity, He took from His humanity. But the preaching of the Gospel grew and was disseminated throughout the whole world. It grows also in the mind of every believer, for no one is suddenly made perfect. But in its growth, not like the grass, (which soon withers,) but it rises up like the trees. The branches of this tree are the manifold doctrines, on which the chaste souls, soaring upwards on the wings of virtue, build and repose.