“The reason Bahá'u'lláh forbade drinking alcoholic beverages”

The reason Bahá'u'lláh forbade drinking alcoholic beverages is because it is bad for the health, more particularly for the mind. Of course you can point this out to Mr.... and Mr.... and you can also pray that they will themselves feel the urge to give it up; but these are habits each individual should seek to surmount for his own good. 

- Shoghi Effendi  (From a letter dated 17 February 1945 written on behalf of Shoghi Effendi to an individual beiever; The Compilation of Compilations, vol. II, Prohibition on Drinking Alcohol)