ירמיהו, פרק י״ז, פסוק כ״ז

A severe consequence hangs over Jerusalem, dependent entirely on how its inhabitants treat the Sabbath. If the people refuse to protect the holiness of this day, a harsh punishment awaits them. The primary approach among commentators is that failing to listen to God directly means ignoring the command to keep the Sabbath holy. This violation takes the practical form of carrying loads and transporting them into the city. Entering the gates of Jerusalem while carrying these burdens is the specific act that breaks the sanctity of the day [רש״י].

If the people choose to ignore this clear warning, God declares that the outcome will be total ruin. He will ignite a fire directly within the gates of the city. This blaze will spread to consume Jerusalem's most magnificent structures, destroying its grand halls and castles. Furthermore, this fire will be unquenchable. It will not fade away on its own, nor can it be put out by human hands, continuing to burn until absolutely everything is completely destroyed.