The Alien Fire Of Alcohol
Our sages examine the sin of Nadav and Avihu, and write that Nadav and Avihu wanted to serve Hashem under the influence of alcohol. They certainly weren't drunkards; on the contrary, they were tzaddikim of the highest level. Their mistake was that they believed they could attain even higher spiritual heights by way of substance usage. Hashem doesn't want "spiritual heights" that result from the alien fire of outside substances like wine, liquor, and drugs of all sorts. These are the alien fires that Hashem doesn't want. Hashem wants our spiritual gain that results from yearning, dedication, perseverance, and hard work.
(Rabbi Shalom Arush)