1. [1/-] al-Kafi: Ali b. Ibrahim from his father from Ibn Abi Umayr from Muawiya b. Ammar from Abi Abdillah عليه السلام, he (Muawiya) said: I said to him: a man forgets to throw pebbles at the pillars [in the Hajj] and departs for Makka, he said: he goes back and throws them [makes up for it] … I said: he misses doing that and leaves [departs back to his land], he said: there is nothing further upon him [he does not have to do anything], I said: what if a man forgets the Sa`i [brisk walk] between Safa and Marwa? He said: he repeats the Sa`i, I said: he misses doing that and leaves? He said: he has to come back and make the Sa`i, this (Sa`i) is not like throwing pebbles at the pillars, throwing is a Sunna while Sa`i between Safa and Marwa is a Faridha.