Hilary of Poitiers
Catena Aurea · Matthäusevangelium 13
Another parable put he forth unto them, saying, The kingdom of heaven is like to a grain of mustard seed, which, a man took, and sowed in his field: Which indeed is the least of all seeds: but when it is grown, it is the greatest among herbs, and becometh a tree, so that the birds of the air come and lodge in the branches thereof.
This grain then when sown in the field, that is, when seized by the people and delivered to death, and as it were buried in the ground by a sowing of the body, grew up beyond the size of all herbs, and exceeded all the glory of the Prophets. For the preaching of the Prophets was allowed as it were herbs to a sick man; but now the birds of the air lodge in the branches of the tree. By which we understand the Apostles, who put forth of Christ’s might, and overshadowing the world with their boughs, are a tree to which the Gentiles flee in hope of life, and having been long tossed by the winds, that is by the spirits of the Devil, may have rest in its branches.