Re: original shia part 2
wait, hasnt the Quranic proof (in shia theology) for infallibility of Ali been covered yet? We trace it to the Hadith e Kissa sourced in Sahih Muslim amongst other Sunni books that basically mentions the nuzool of an ayah and explains that five people from the Ahl e bayt were the intended target of that Infallibility verse.
so you see, the infallibility wasnt by-the-way, it wasnt something the Prophet just said, the Prophet gathered five people into his cloak and an ayat was revealed about the purification of these five people. it IS mentioned in the Quran, depending on who u ask ofcourse.. :)