Today’s commandment comes from Amy Einsohn’s Copyeditor’s Handbook.
Copy editors do not develop or rewrite text; they make text clear and coherent. If the copy editor is confused by a text, readers will be, too. But the copy editor doesn’t assume the author’s meaning; the copy editor queries the author about ambiguities.
Queries should be framed in terms of what readers want, expect, or need. Along with the query, a good copy editor will offer suggestions for improvement.
As far as commandments go, this one is as easy as “thou shalt not murder.” (I’m not the only person who finds that particular Old Testament commandment easy-peasy-lemon-squeezy, am I?) After all, a good copy edit by definition makes text clear, coherent, correct, and consistent.