Following the tragic deaths of Aaron's sons, the remaining priests receive a strict directive requiring absolute mental clarity. The demand to avoid wine and intoxicating drinks is not merely a technical rule for entering the Tabernacle, but a fundamental necessity for maintaining the spiritual and legal boundaries that sustain daily life.
The primary approach among commentators is that the requirement for sobriety serves a highly practical purpose: ensuring the priest can accurately maintain distinctions during his service [רש״י, משכיל לדוד, דברי דוד]. A priest must remain completely sober to guarantee that the Temple service is performed in a state of holiness and is not profaned, as any service performed while intoxicated is completely invalid. In this view, distinguishing between the pure and the impure refers to the practical ability to identify who is fit to participate in the service and who is forbidden. Another perspective suggests that sobriety is tied to an entirely separate and independent responsibility: guiding the nation [ביאור יש״ר, הכתב והקבלה, שטיינזלץ]. Because alcohol blurs the mind, an intoxicated person is prone to making mistakes when issuing legal instructions [ספורנו, רשב״ם, שד״ל]. A more direct interpretation views this requirement as an active, urgent command directed at Aaron and his sons, emphasizing that despite their heavy mourning, they must not abandon their public duties as teachers of the law [פירושי רד״צ הופמן].
The act of distinguishing between the holy and the mundane involves separating sacred places, times, vessels, and offerings from ordinary ones [ביאור יש״ר]. Beyond physical separation, several commentators explain that this also applies to the financial valuation of items people dedicate to the Temple. A priest must possess absolute clarity to accurately appraise the value of sacred objects before they can be redeemed and returned to ordinary use [מזרחי, מלבי״ם, חזקוני, תורה תמימה]. Furthermore, the responsibility to separate the impure from the pure sets the stage for upcoming laws concerning permitted and forbidden animals, leprosy, and bodily impurities [אבן עזרא]. Establishing whether something is pure or impure is not always a matter of theoretical legal discussion; it often requires a tangible, visual examination, such as inspecting a mark of leprosy. Therefore, complete sobriety is critical not only when teaching the law, but at the very moment of looking at an affliction and determining the physical reality [תורה תמימה, מלבי״ם].
Beyond the practical laws, the prohibition against drinking carries a profound psychological and spiritual dimension. God knew the priests were immersed in deep sadness. Instead of allowing them to seek comfort in wine, which merely makes a person forget, He provided a different path to lift their spirits and distract them from their mourning: the deep study of Torah. The process of clarifying legal uncertainties and precisely defining the boundaries between the holy and the mundane brings a deep, inner happiness, as there is no joy quite like the resolution of doubt [העמק דבר]. Ultimately, this strict demand for mental clarity is not limited to the priests in the Tabernacle. It extends to any wise person or teacher in Israel, who must carefully avoid anything that might disrupt their understanding and cause them to alter even the smallest detail of God's laws [שד״ל, מזרחי].