יחזקאל, פרק מ״ד, פסוק כ׳

Priests serving in the Temple are required to maintain a dignified and precise physical appearance. A key part of this presentation involves finding a careful balance between two extremes of hair care. On one hand, they are forbidden from completely shaving off their hair [רש״י, מצודת ציון]. This rule specifically distances them from the practices of ancient Egyptian priests, who were known to shave their heads entirely [ביאור שטיינזלץ]. On the other hand, they cannot neglect their hair, allowing it to grow wildly and spread in every direction [רש״י, מצודת דוד, ביאור שטיינזלץ].

To ensure their hair never becomes long and unkempt, fixed schedules were established for haircuts. A regular priest is required to cut his hair once every thirty days. By comparison, a High Priest receives a haircut every Friday, while a king has his hair cut every single day [רד״ק, אברבנאל, צאינה וראינה].

The proper and balanced approach requires the priests to trim and arrange their hair evenly. The primary approach among commentators is that this means maintaining a neat, handsome haircut that avoids both complete baldness and wild growth [רש״י, רד״ק, ביאור שטיינזלץ, צאינה וראינה]. However, some commentators offer a more vivid picture, comparing the required haircut to spelt, a type of grain [מצודת ציון, מלבי״ם]. In a stalk of spelt, the kernels are perfectly layered so that the top of one kernel touches the root of the one beside it. The priests' hair is meant to be styled in this exact, overlapping manner [רש״י, מצודת דוד]. This unique, curled style was traditionally known as the "haircut of Ben Elasah." While it was originally the signature look of the High Priests, the instruction here expands the requirement, directing all regular priests to adopt this highly dignified appearance as well [רד״ק, מלבי״ם, אברבנאל].