Matthew Henry on Isaiah 28:23-29

The husbandman applies to his calling with pains and prudence, in all the works of it according to their nature. Thus the Lord, who has given men this wisdom, is wonderful in counsel, and excellent in his working. As the occasion requires, he threatens, corrects, spares, shows mercy, or executes vengeance. Afflictions are God's threshing instruments, to loosen us from the world, to part between us and our chaff, and to prepare us for use. God will proportion them to our strength; they shall be no heavier than there is need. When his end is answered, the trials and sufferings of his people shall cease; his wheat shall be gathered into the garner, but the chaff shall be burned with unquenchable fire.