Isaiah 28:28 - Ellicott's Commentary On The Whole Bible

Bread corn is bruised. — Better, as a question, Is bread corn crushed to pieces? As the poor and meek of the earth were as the fennel and the cummin, so Israel, in its national greatness, was as the “bread corn” of the wheat and barley. For this a severer chastisement, a more thorough threshing, was needed; but the end of threshing is the preservation, not the destruction, of the true grain. It is for a time, not for ever. It separates the worthless from the precious. The wheels stop when they have done their work.