Why did Aharon’s sons die? Because they sinned and brought “strange fire” to the altar (Lev. 10:1).
Some of the sages identified the strange fire with drunkenness: “It was because they came into the sanctuary drunk with wine”.
A chassidic teacher objected to this interpretation. “Are we not commanded to serve the Lord with joy (Psalm 100:2)?” he asked. “And doesn’t the Psalmist say that wine brings joy to the human heart (Psalm 104:15)? Why then should we object if two priests imbibe wine in order to serve God with a happy heart?”
He thought about his own question and decided that serving God with joy did not mean getting oneself artificially high from alcohol but feeling a sense of spiritual ecstasy at being so close to the Divine Presence.