
Jerome
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.
The kingdom of heaven is the preaching of the Gospel, and the knowledge of the Scriptures which leads to life, concerning which it is said to the Jews, The kingdom of God shall be taken from you. (Mat. 21:43.) It is the kingdom of heaven thus understood which is likened to a grain of mustard seed.