The Modern Translation
Solomon's point is that your reply is not a verdict on your coworker. It is a lever on the temperature of the room. The email with six people copied is already hot, and every sharper sentence you add is fuel. So before you type "again," notice what you actually want. You want the answer, the project moving, and nobody in the thread remembering Monday as the day you went to war over a paragraph on page two. A soft answer does all of that. It can be one line: "Thanks, I found it in your earlier note. I'd missed the deadline detail, so I'm updating the plan now." You give up nothing, and you hand the sender no new grievance to quote back. Notice, too, that the manager on the copy line reads tone faster than content. The soft reply is also the one that makes you look like the person who can be trusted with the next, bigger thread.
The Text-Message Version
Try It Today
Today, the next time a message stings, write your angry reply in a blank document and do not send it. Then write a second reply with one calm sentence and one concrete next step, and send that one. Wait for the answer. Notice whether the tone of the thread shifts in the following exchange, and how much less of your afternoon the soft version took.