Milkhemet Mitzvah
Milḥemet mitzvah or in Tiberian Hebrew milḥemeth miṣwah (Hebrew: מלחמת מצווה, lit. "war by commandment", or what is often termed a "religious war", a "war of obligation," a "war of duty" or a "commanded war") is the term for a war during the times of the Tanakh when a king (of the Kingdom of Israel) would go to war in order to fulfill something based on, and required by, the Torah without needing approval from a Sanhedrin, such as war against Amalek, or the seven nations of Canaan.