Leviticus 10:10

And that ye may put difference. — The motive here assigned for their abstinence from intoxicating liquor is, that by keeping sober they might be able to discriminate between the legal and illegal points in the prescribed observances, which required the greatest care. Thus, for instance, the rules as to which places and days and sundry portions of the offerings were holy or common, or as to holy fire and common fire, which Nadab and Abihu violated; or about ceremonially clean and unclean men, women, animals, and utensils. (See Ezekiel 44:23.)