Why do Amish men have beards, but not mustaches?
There are quite a few scriptures that mention beards in the Bible. An example would be Psalm 133:1,2. An Amishman does not shave his beard after he becomes married. A long beard is the mark of an adult Amishman. Mustaches, on the other hand, have a long history of being associated with the military, and therefore are forbidden among the Amish people.