Muhammad Khazri in tesAT-TASHRM i JL ISLAM!
Muhammad Khazri in tesAT-TASHRM i JL ISLAM! says: "Hazrat Abu Abdullah Jaffer Sadiq (A.S) came of the Sayyeds of the Holy Household. He won the title of Sadiq because of his unchallengeable truthfulness." Batras Bustani inhis DAERATAK MAAREFVol VI. reaffirms this view. Another explanations is, there was a need to distinguish him form others who had a similar name and who had made false claims to be the Imam of the time. By calling him AL-SADIQ, people would differentiate him from the false ones.
A third explanation is that Allah, the Almighty, Himself chose this title for him. The Prophet (S. A. W. W.) therefore foretold the birth of this Imam and gave him this title. The most important thing to note is that like the Prophet (S.A.W.W.) who was acknowledged to be truthful i AL-SADIQ) even by his avowed enemies, The Quraish of Mecca, similarly Imam Jaffer Sadiq's truthfulness has been accepted at all times even by his enemies. As for the name Jaffei; by.
Arabic lexicon, it simpK means a stream. But according to some traditions. Jaffer is a unique stream in paradise. In view of the fact that Imam Jaffer (A.S) was to become a fountain head of knowledge for all and sundry; he was given this name by his father, the Fifth Imam. The Sixth Imam is also known by many other titles C1LQAB') that include FAADHIL (the excellent one), TAHIR (the pure one), SAB1R (the patient one), QAEEM (the steadfast one) and MUSADDIQ (the ratifier).
Another unique thing about Imam Jaffer Sadiq (A.S) is, the Shia sect of Islam is named after him. Thus when people talk of the 'madhab' of Abu Hanifa, of Ahmed Ibne Hanbal, of Malik bin Anas, of Imam Shafi, they talk of the madhab of Ahlul Bayt as madhab Jafferi. HIS PARENTS AND GRANDPARENTS: His father was Imam Muhammad Baqir (A.S.). His mother was Fatima (popular by the name of Umm Farwa). She was a woman of many merits.
Imam Sadiq (A.S.) had high regards for her, so much so that he used to quote her as source of "hadith' from the Fifth Imam.
One such hadith is recorded by Kulayni in USULAL-KAFI: Imam Sadiq (A.S.) reports that his father told Umm Farwa: "O Umm Farwa, I pray to Allah for the sinners among the Shias day and night, a thousand times, for we Imams endure the misfortunes that happen in the light of what we know of the coming reward, whereas they suffer without such knowledge." This does not come, as a surprise knowing the fact that Umm Farwa's father was Qasim, the son of Muhammad Bin Abu baqr.