כי תצא למלחמה על אויביך
Rashi comments that the Torah is speaking about a milchemes reshus, discretionary war. With regard to milchemes mitzvah, a war which we are commanded to wage, such as against the sheva umos, seven pagan nations that inhabited Eretz Yisrael, we are enjoined not to take prisoners. Thus, the subsequent law regarding the yefas to’ar, beautiful captive, would not apply. The Baal Shem Tov also applies this pasuk as a metaphor for the never-ending battle we must wage against our internal enemy: the yetzer hora, evil inclination. We have no shortcuts in this battle. It is constant, so that it demands…