Musar sobre Exodo 35:3

לא תבערו אש בכל מושבותיכם ביום השבת. The word "fire" here is an allusion to the destructive fire engendered by strife and anger. One needs to be careful not to allow oneself to become angry so that the fire of that hatred should not consume one. The "fire" is an allusion to the fire of purgatory that one would suffer from as a result..

When G–d began the work of Creation, He said: "Let there be light," the foundation of fire. There is both visible and hidden fire. This is the mystical dimension of the Torah's commandment in Exodus 35,3: לא תבערו אש בכל מושבותיכם ביום השבת. "Do not light a fire in any of your dwellings on the Sabbath day." The Torah singled out this prohibition of work (whereas none of the other 38 basic prohibitions of work is named).