Leviticus 10:9

And when ye reap the harvest of your land, thou shalt not wholly reap the corners of thy field, to the very edge of the property line, neither shalt thou gather the gleanings of thy harvest, single stalks and ears that dropped when the sheaves were bound.

Do not drink wine nor strong drink, the latter being a very strongly intoxicating beverage made from barley, dates, and honey, thou, nor thy sons with thee, when ye go in to the Tabernacle of the Congregation, when engaged in the duties of the priesthood, lest ye die; it shall be a statute forever through out your generations; it was practically equivalent to absolute prohibition in the case of Aaron and his sons, for they must have been on duty continually, especially in the early days: later the priests were on duty in the Sanctuary only a short time during the year;