• Use the passive when you want to de-emphasize the doer. That is, the thing acted on is more important that the actor. The clothes were received by the two grateful refugees.
• Use the passive when you want to command or give your words authority. Smoking is not permitted in this building is stronger (and less argumentative) than you may not smoke in this building.
• Sometimes the person doing something isn't significant and you want to emphasize the action. Twila Belk was arrested at noon yesterday. Who arrested her may not be important.
• Use the passive to emphasize the receiver of the action. The New Testament speaks of Jesus being raised from the dead. It's an important theological point. (John 2:22 is one example.)
• Use the passive when you want to have a punch line: The gold medal in the triathlon competition was won by a ten-year-old girl. This withholds the information until the end of the sentence.
• Use the passive when you want to achieve a rhythm and the cadence determines the style. Someone pointed this out to me: Robert Frost could have written, "I took the road where not many people travel," but note the cadence of "I took the road less traveled by."
It's not a sin to use the passive voice, but it's a serious misdemeanor when you avoid it because you're afraid of breaking a rule.
(And now, an unapproved message from Twila Belk: "Excuse me for butting in here, but I beg to differ with you. If I was being arrested yesterday, it is of extreme importance to me to know who I was being arrested by." After she wrote that sentence, she wondered if she had committed a serious crime. "Oh oh," she said, "the grammar police will really be after me now. I might be arrested again. But this time I'll know who did it.")