In the hours after a malfunctioning hot plate started a fast-moving blaze that killed seven brothers and sisters in an Orthodox Jewish neighborhood of Brooklyn on Saturday, a Fire Department official went door to door at nearby homes handing out pamphlets titled “Fire Safety for Jewish Observances.”

“Stay in the kitchen — don’t leave cooking food unattended,” warned the first item on the list of precautions.

For observant Jews, that admonition is hard to reconcile with the religious tenets that govern how they are to behave on the Sabbath, the weekly day of rest. From sundown on Friday until sundown on Saturday, those who observe the Sabbath do not work, write, use electricity — or cook. If they want a hot meal during that time, they must prepare their food — often a popular stew called cholent — ahead of time and leave it warming overnight.

While the household sleeps, the Saturday meal is kept warm either on an electric hot plate or atop what is known in Yiddish as a blech, a metal plate that sits on a gas burner set to low. Fire Department officials said the fatal fire in Midwood, Brooklyn, in an observant Jewish household, had started with a malfunctioning hot plate sitting on a first-floor kitchen counter.