I am trying to determine all the differences between sunnis and shiites. Can you tell me how different are their ways of praying? Why do certain people view as their kalima to be wrong as there is a small addition at the end of the shii version? I want my concepts to be clear as the masses view shiites as non-Muslims in many regards. Is there any relevant proof in document (a fatwa) that says that the shii school of thought is right?
I would like to first clarify two points about Shia:
1. No individual or group has any authority to declare the followers of a sect of Islam, Non-Muslims. It is only the jurisdiction of the Muslim community, in its collective capacity, that may take such a decision. Even then, as long as the person believes in the fundamentals of Islam, reads his prayers and pays zakah, then according to the Qur'an, he should be considered a Muslim. This most definitely applies to Shia Muslims.
2. The main difference between Shia Muslims and the mainstream Muslims is in their beliefs. The differences in practices are only secondary and such differences can be found among non-Shia Muslims as well.
In terms of belief, the difference between Shia Muslims and the mainstream Muslims is that Shia Muslims believe that after the Prophet (sws) certain individuals (Imams) from among his Ahl Al-Bayt and generation are to be followed. They consider these individuals to be divinely appointed, infallible and being divinely guided. According to Shia the last Imam has been gone to occultation about 1000 years ago but is still alive and will reappear to bring justice to the world and he is Mahdi.
Obviously as the Qur'an is our book of guidance, one needs to look at the Qur'an to see whether the Qur'an directs us to hold the above belief.
In terms of the differences in prayers, these differences are mostly in details. I am not sure if this is what you are interested in but if you are interested please write back and we will list these differences for you.