1. [1/-] al-Kafi: Ali b. Ibrahim from his father from Uthman b. Isa and al-Hasan b. Mahbub all together from Sama’a from Abi Abdillah عليه السلام, he (Sama’a) said:

I asked him about a man who is answered oppositely by two of his co-religionists (i.e. Shi’as) in regards to a matter – both transmitting it [their answers – on your authority], one of them obligates it while the other forbids it – what should he do? he said: he withholds [doing anything] until he accesses one who will inform him (of the true position), and he is respited until such a time as he meets him. [And in another narration [the Imam said]: whichever of them you act by – suffices you – if done in subservience (with the intention of obeying)].