680. Kindling and Extinguishing

Shabbos 12:1

Lighting even the smallest fire renders one liable so long as he needs the ash that doing so creates. If a person lights a fire with a purely destructive intent, he is not liable. If someone sets fire to a pile of produce or a building belonging to another person, he is liable because his intention is to take vengeance against this person and doing so calms him down by serving as an outlet for his anger. This is comparable to a person who tears his garments in grief for a deceased person or in a fit of anger, or a person who injures another person in a quarrel. All of these are considered constructive activities. Similarly, if a person lights a candle or a torch for warmth or light, he is liable. One who heats iron in order to temper it is liable for performing a subordinate labor of kindling.

Shabbos 12:2

A person who extinguishes even the smallest fire is liable, including both extinguishing a candle and extinguishing a coal made from wood. One who extinguishes a glowing piece of metal is not liable unless his intention is to purify the metal. This is what blacksmiths do: they heat iron until it glows and then extinguish it in water to temper it. One is liable for this as a subordinate labor of extinguishing. One is permitted to extinguish a glowing piece of metal in the public domain in order to prevent injury to the public. Adding oil to a burning lamp renders one liable for kindling; removing oil from a burning lamp renders one liable for extinguishing.