In the Old Testament, fire was a purifying element. The sacrifices were burnt because the Jews believed that their sins were transferred to the animal on the altar, and the burning devoured these sins and sent the aroma of repentance to the God above. In his letter to the Romans, St. Paul takes this idea a step further, adapts it to fit Christianity and says that we should offer our bodies as living sacrifices, making our very lives offerings to God, making our lives blazing, constant, purifying fires. Fires that burn, spark, and glow. Fires within. This same fire urged Teresa of Avila to reform her religious order, which had fallen into laziness and wealth. It drove her to sit for hours praying whether she felt anything or not. It's a fire that isn't extinguished unless we kill it, heaping buckets of lukewarm water on the blaze.