Be quiet!

be quiet

A command to stop talking or making any noise. Often (but not exclusively) said as a harried imperative. Be quiet! Do you want them to hear us? Kids, please be quiet—your mother has a headache.
See also: quiet
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

Be quiet!

Stop talking or making noise. (Regarded as a bit harsh or overbearing, but made polite with please.) Bill (entering the room): Hey, Tom! Tom: Please be quiet! I'm on the phone. Tom: Hey, Bill! Bill: Be quiet! You're too loud. Tom: Sorry.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also:
References in classic literature ?
be quiet!" exclaimed the hunter between his clenched teeth, and without turning his eyes from the bear.