
Gregory the Great
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.
(Mor. xix. 1.) Christ Himself is the grain of mustard seed, who, planted in the garden of the sepulchre, grew up a great tree; He was a grain of seed when He died, and a tree when He rose again; a grain of seed in the humiliation of the flesh, a tree in the power of His majesty.