כי תצא למלחמה על אויביך ונתנו ה’ אלקיך בידך

רש”י: לא דברה תורה אלא כנגד יצר הרע

The posuk can also refer to fighting the “yetzer hara.”

One of the reasons tzitzis are worn is to protect oneself from sin. The mitzvah of tzitzis requires 32 strings attached to the garment. Halacha implies that 31 strings are also considered kosher, but for the tzitzis to fully protect from sin, one shall be more stringent and wear with 32 strings.

The words from רש’’י imply this message.

 ל’’א דברי תורה – the gematria of ל’’א =31 strings is kosher according to the Torah, but, רש’’י continues, אל’’א = 32 – the 32 strings required to battle the yetzer hara and protect oneself from all sins.

(כ”ק מרן מהר”ש מבעלזא זי”ע)