Hating Evil Completely

במדרש על יהושע ימים רבים עשה מלחמת כו'

In the Midrash it is taught regarding Yehoshua, "For many days he waged war," and so on.

The Midrash asks why Yehoshua dragged out his wars over many days rather than finishing them quickly.

לתרץ מעשה יהושע נראה כי זמן מלחמתן של ישראל הם מקבלין כח וחיזוק כענין שכתוב לחמנו הם וכ' על אנשי המלחמה שיניך כעדר הקצובות שנק' אכילה כמ"ש ואכלת כו' אויביך ולכן הי' כוונתו לטובה

To resolve the conduct of Yehoshua, it appears that during the time of the wars of Bnei Yisrael they receive strength and reinforcement, in the sense of what is written, "They are our bread" (Bamidbar 14:9) — said of the men of war — "Your teeth are like a flock of ewes," for this is called eating, as it is written, "And you shall consume... your enemies" (Devarim 7:16); and therefore his intention was for the good.

The Sfas Emes answers that during their wars Bnei Yisrael draw spiritual strength, since vanquishing their enemies is a form of consuming and absorbing the good buried within them, so Yehoshua's prolonging of the war was actually for a positive purpose.

אך מרע"ה ששנא כ"כ הרשעים שלא [*הי'] יכול לסבול שיהיו קיימים אף שעה אחת אף שיצמח מהם טובה

However, Moshe Rabbeinu, who hated the wicked so intensely that he could not bear that they remain in existence even for a single hour — even though good might sprout forth from them.

Moshe Rabbeinu, by contrast, so despised the wicked that he could not tolerate their continued existence for even a moment, even if some good might eventually emerge from them.

וכן צריך להיות אדם השלם:

And so too must the complete person be.

And this uncompromising hatred of evil, says the Sfas Emes, is the standard to which the truly complete person must aspire.

Summary: The Sfas Emes takes up the Midrash's question of why Yehoshua prolonged his wars over many days. He explains that the wars of Bnei Yisrael are themselves a source of strength and reinforcement, for conquering the enemy is likened to eating and consuming them — drawing out and absorbing the good hidden within them — and thus Yehoshua's delay was for a constructive end. Moshe Rabbeinu, however, stood on a loftier level, hating the wicked so completely that he could not abide their existence even for an hour, even at the cost of forgoing whatever good might one day sprout from them. The Sfas Emes concludes that this total intolerance of evil is the measure of the complete person.