Grain for bread must be ground, but it is not endlessly threshed. Though the wheels of the cart roll over it, the horses do not crush it.
Jewish Publication Society of America Version (JPS1917) - Isaiah 28:28 >Is bread corn crushed? Nay, he will not ever be threshing it; and though the roller of his wagon and its sharp edges move noisily, he doth not crush it.