What happens to troops if the trumpeter just blares out random sounds instead of the right commands?
If the trumpeter blares random sounds rather than the particular sound for each command, the troops cannot know whether to retreat, attack, or otherwise act. They are left confused, sitting and looking at each other, asking what they are supposed to do, because no clear command is understood.
Les explains that in the Roman army, when the trumpet was blown right, the soldiers knew whether to retreat, attack, or whatever. But if the trumpeter did not know his commands and just blared out a bunch of sounds, the poor troops would be sitting there looking at each other, confused, asking, “What are we supposed to do?” Les ties this to Paul’s analogy in verse 9: unless you utter by the tongue words easy to be understood, it will not be known what is spoken; you speak into the air. He also illustrates the point with a deep theologian’s complicated writing that neither he nor his wife could understand until it was put into plain, ordinary layman’s language, showing the same confusion happens when men talk above the heads of average individuals.