Leviticus 19:27 states: “Do not round off [the hair] at the edges of your heads.” Our Rabbis interpreted the term “edges” to refer to the hair between the ears and the hairless portion of the face. Maimonides writes:1

Our Sages did not determine the amount of hair which must be left at the corners of our temples. We have heard, however, from our elders that one must leave at least forty hairs.2

One may remove the [hairs from] the edges [of our heads] with scissors. The prohibition applies only to total removal with a razor.

In one of his responsa, Maimonides clarifies that the forbidden area is about the size of a thumb. The Shulchan Aruch (Yoreh De’ah 181:1) explains that we are speaking about the area where the skull is joined to the jawbone. The Kitzur Shulchan Aruch 170:1 states that the area which is forbidden to be shaven extends until below the ear, the place from which the jaw protrudes.

Although the person who violates the prohibition is the one who actually shaves the hair off, if the person having his head shaved moves his head to assist the person doing the shaving, he also is considered as having transgressed. Even if a person does nothing at all, it is forbidden for him to allow the edges of his head to be shaven.3

Maimonides4 considers this prohibition as one of the safeguards against idolatry. He explains that it was customary for pagan priests to shave the corners of their heads. Hence, the Torah commanded the Jewish people to shun this practice.5 The Chasam Sofer6 explains this concept further: Since pagans could not have their idols grow hair, it was customary for them to shave their own hair, so that they would resemble the images they worshipped. Others offer different rationales for the practice.

The rationale, however, is not significant. The prohibition is one of the 613 mitzvos of the Torah,7 incumbent on all Jewish males, at all times and in all places.

As mentioned above, the upsherinish is instituted to train the child to observe this prohibition. But the prohibition applies not only in childhood, but throughout our lives. And unfortunately, it is violated sometimes, unknowingly all too often. For when a barber shaves the hair at the side of the ears, a transgression, equal in severity to partaking of pork or shrimp, is committed.

In many communities, because the Torah singled out this portion of the hair for distinction, it is customary to allow the hair to grow long, thus creating the “earlocks” (peyos) that have become part of the stereotype image of the observant Jew. Significantly, this custom is practiced by Jews from such far-removed origins as Yemen, Morocco, and Eastern Europe.

The AriZal, however, would not grow his peyos below his ears. Instead, he would trim them with a scissors.8 The Lubavitch custom is to follow this example.9