Glossa Ordinaria — as excerpted in the Catena Aurea on Luke 13:18-21

“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.)”