“… Six cities of refuge shall serve for you…” – Bamidbar 35:13

שֵׁשׁ עָרֵי מִקְלָט תִּהְיֶינָה לָכֶם – במדבר לה, יג

The Sefer Hachinuch enumerates six mitzvos that are obligatory constantly; “their obligation does not depart from the person for a single moment throughout his lifetime.” These are:

1) To believe in G‑d.

2) Not to believe in any power other than Him.

3) To acknowledge His oneness.

4) To love Him.

5) To fear Him.

6) Not to stray after the thoughts of our hearts and the sight of our eyes.

“These six are symbolized,” says the Sefer Hachinuch, “by the verse, ‘Six cities of refuge shall serve for you.’”

Like all aspects of the Torah, even this memory technique is laden with meaning.

The six Cities of Refuge provide protection for a person who accidentally caused someone’s death. So long as he is within a City of Refuge, he is safe from potential avengers of the deceased’s blood.

The avenger of the deceased’s blood is a metaphor for the yetzer hara. For as the Talmud (Bava Basra 16a) teaches, the yetzer hara, our evil inclination that incites us to sin and the mal’ach hamovess, the Angel of Death that avenges the sin are one and the same. It follows that the protection provided by the Cities of Refuge is likewise metaphoric of a means of protecting ourselves from the yetzer hara.

Now, all the mitzvos that we performprovide us with the spiritual enrichment necessary to grapple with the yetzer hara. Most mitzvos, however, are obligatory only in specific times; hence, the protection they provide is also limited. Yet the yetzer hara’s efforts to tempt man to sin are not limited to any specific time or place. Rather, “The impulse of man’s heart is evil from his youth” (Beraishis 8:21)—non-stop. Therefore, in order to assist us in our constant struggle, G-d gave us six mitzvos that must be observed constantly. Their observance serves as the “Cities of Refuge” that provide us twenty-four hour shelter from the yetzer hara’s constant threat.

—Sefer Hasichos 5747, vol. 2, pp. 492-493