Well, Sunni Muslims believe in four Califs after the holy prophet S.A the fourth of which being the first Imam of Shia Muslims. However, they respect all The Fourteen Infallibles (not sure about how they believe in Imam Mahdi Aj. though) in Shia Islam according to both Quran (verses about Ahl-ol-Beit A.S.) and Hadith from the holy Prophet S.A. . Now the question is if Sunni Muslims agree on that the holy prophet of Islam has given the title of Sadiq (honest and truthful) to the sixth Imam of Shia Muslims, Imaam Ja'far Sadiq A.S., why they do not follow the teaching of him, being introduced as truthful by the holy prophet, instead of e.g. his students not being nominated to any attribute by the holy prophet S.A if I am right?
To me, if the holy prophet has accepted such a position for 13 people after him among all his companion and children (children of Fatimah S.A. to be more explicit), God being talked about them as them being infallible (Al-Ahzab:33) then why a Muslim may follow others talking different than those holy and innocent people? I mean if they were wrong they were not of such a position in the eyes of prophet and for Allah, were they? And if they are not wrong why to follow others giving Fatwa sometimes in complete different ways?
Hope that the question is clear enough for the answers also to be clear.
To emphasize the point in question let put the matter as follows:
If I was a non-Muslim and I was to become a Muslim, just after confessing in uniqueness of Allah Azza-va-Jalla and that Muhammad --peace be upon him-- is his prophet I required first to know which school in Islam to obey. If I have no precise knowledge of Quran and Hadith, when all Muslim brothers know their own school to be the right one, how can I decide which one to follow? Maybe there should be a hint for me to decide, based on Quran or/and Hadith equally accepted by all different schools of Muslims. If it is a relevant expectation, then does there exist any hint in Quran or/and Hadith accepted by all Muslim brothers? Shia claims there are some, and maybe many, one of them is asked about here, that Sadiq (truthful) is an attribute (and not a forename) accepted by all Muslim brothers to be given to Imam Ja'far-ibn-Muhammad Sadiq by the holy prophet --peace be upon him-- around a century before Imam's birth date, and that Imam Sadiq --peace be upon him-- is one from whom the majority of Shia's Fiqh is derived. That is Shia Muslims believe majority of their Fiqh is already approved by the holy prophet --peace be upon him-- when he called his son "Al-Sadiq". Is this hint acceptable by Sunni brothers? And if not, do they have their own hints to override this and the other hints used by Shia brothers? Do such hints exist for all the branches of the Sunni's, Hanbali, Shaafe'ee, Maaleki, and etc.? That is, if it is proved to someone that Shia Islam is not the one which should be followed, does exist a hint that explain which Sunni school should he follow then?
In other words, the questioner tries to understand why Sunni brothers don't agree upon the Shia's hints, and that do they have their own hints then or not?
NOTE: I am trying to ask the question as neutral, I really want to know if these reasoning by Shia Brothers are considered as reasonable or unreasonable by other Muslims, and if not reasonable then why? And that if the answer to the previous question is no then what is their own reasonable hints (
based on Quran and Hadith accepted by all the Muslims) to prefer their own school over the Shi'ite's based on them? This is a general question with a general scope but at the same time I have specified its scope to one single question about Imam Sadiq --peace be upon him-- for the question to meet the conditions of an acceptable question to Islam.SE.