Q: Why Shias beat themselves up and cut them selves in Muharram?
A: There is no such traditions practiced by any of our Imams. If we are to follow the traditions of our Imams such acts were not carried by them. When you are saddened by the event the following hadith is our guide line:
Imam Reza (A.S.) said (to Reyyan Ibn Shabib):
O' Son of Shabib! If you have to cry over something, then do so over Husain Ibn 'Ali (A.S.) for surely, he was slaughtered in the manner in which a ram is slaughtered.
Bihar al-Anwar/ Vol.: 44/ pg.: 286.