12 . . . and he will thoroughly cleanse his floor and gather his wheat into the barn; but the chaff he will burn with unquenchable fire.
Pseudo-Chrysostom: “The floor,” is the Church, “the barn,” is the kingdom of heaven, “the field,” is the world. The Lord sends forth His Apostles and other teachers, as reapers to reap all nations of the earth, and gather them into the floor of the Church. Here were must be threshed and winnowed, for all men are delighted in carnal things as grain delights in the husk. But whoever is faithful and has the marrow of a good heart, as soon as he has a light tribulation, neglecting carnal things runs to the Lord; but if his faith be feeble, hardly with heavy sorrow; and he who is altogether void of faith, however he may be troubled, passes not over to God.
The wheat when first thrashed lies in one heap with chaff and straw, and is after winnowed to separate it; so the faithful are mixed up in one Church with the unfaithful; but persecution comes as a wind, that, tossed by Christ’s fan, they whose hearts were separate before, may be also now separated in place. He shall not merely cleanse, but “thoroughly cleanse;” therefore the Church must needs be tried in many ways till this be accomplished.
Rabanus: There is this difference between the chaff and the tares, in that the chaff is produced of the same seed as the wheat, but the tares from one of another kind. The chaff therefore are those who enjoy the sacraments of the faith, but are not solid; the tares are those who in profession as well as in works are separated from the lot of the good.
Scripture from the Douay-Rheims Bible. Commentary from St. Thomas Aquinas, Catena Aurea, Vol. I (London: Rivington, 1842).