“What is straw to the wheat.” The process of threshing and winnowing left the grain divided into the straw (the broken pieces of shaft that were straw and chaff) and the wheat, the edible part that sustained life. God is making the point that just as there is a huge difference between the straw, which cannot be eaten, and the wheat, which is the very “staff of life,” so too there is a huge difference between His Word, which are the words of life, and the lies of the false prophets, which lead to death.