Hebrew, “Judgement.” Gevurah is Din, the essence of judgment. If we are saved, the Holy Spirit cleanses us with Fire. However, if we are wicked we are burned as those same flames become Hellfire. Gevurah then is both God’s mode of perfecting the Saints and punishing the wicked; judging humanity in general. It is the fulfillment of the Law, and strict meting out of justice. It stands in contrast to Chesed, though Christ’s mercy in Chesed will protect us from Genurah’s fire.
It is because of Chesed that Gevurah is associated with the power to bestow goodness upon others, the cleansing fire becoming Christ’s light of Creation. Gevurah allows one to overcome the true enemies, be they from without (Satan) or from within (Ego).
See Book of Remembrance 4:59, 29:5, 9, 33:16-18.