The Ithna Ashari sect of Shi’a are particularly known for their enmity toward the vast majority of the Sahaba (the Prophet’s Companions), with only a handful of exceptions. The Holy Qur’an announces the fact that Allah is pleased with the Saabiqoon al-Awwaloon from among the Muhaajireen and Ansaar (Sura 9:100), which includes the likes of Sayyidina Abu Bakr al-Siddiq, Umar al-Faruq, Uthman Dhun-Nurayn, and Ali al-Murtada (Radiyallahu anhum).
However, the Ithna Ashari sect disregard Ahadith reported from the Prophet (peace be upon him) via most of his companions, including Sayyidina Abu Huraira and the mother of the believers, Sayyida A’isha (Radiyallahu anhuma), and these two Companions of the Prophet are the ones who narrate the highest number of traditions from the Prophet (Sallallahu ‘alaihi wasallam). The Ithna Asharis only accept Hadith from the Prophet narrated via the Ahlul Bait (alaihimus salaam) and select Companions, such as Abu Dharr al-Ghifari, Salman al-Farisi, Ammar b. Yasar, Miqdad, Bilal b. Rabah, and a handful of others. This despite the fact that the Prophet had approximately 144,000 Companions.
However, it is reported from the sixth Imam of the Shi’a, namely, Imam Ja’far al-Sadiq (Rahimahullah), that he considered all of the Prophet’s Companions to be truthful with regard to their narrating Hadith from the Prophet (peace be upon him):
عن منصور بن حازم قال: قلت لأبي عبد الله عليه السلام: ما بالي أسألك عن المسألة فتجيبني فيها بالجواب ثم يجيئك غيري فتجيبه فيها بجواب آخر؟ فقال: إنا نجيب الناس على الزيادة والنقصان، قال: قلتُ: فأخبرني عن أصحاب رسول الله صلى الله عليه وآله وسلم صدقوا على محمد أم كذبوا؟ قال: بل صدقوا، قال: قلت فما بالهم اختلفوا؟ فقال: أما تعلم أن الرجل كان يأتي رسول الله صلى الله عليه وآله وسلم فيسأله عن المسألة فيجيبه فيها بالجواب ثم يجيبه بعد ذلك ما ينسخ ذلك الجواب فنسخت الأحاديث بعضها بعضاً
Ali ibn Ibrahim has narrated from his father from ibn abu Najran from ‘Asim ibn Humayd from Mansur ibn Hazim who has said the following. “I said to (Imam) abu ‘Abdallah (a.s.), ‘It is confuses me that when I ask you a question and you give an answer and then other person comes and you give a different answer for the same question.’” The Imam replied, “We answer people in a larger and reduced forms.” I then asked, “Did the Sahabah, companions of the holy Prophet speak the truth or lies when narrating his Hadith?” The Imam replied, “They spoke the truth.” I then said, “Why then they have differences?” Have you not considered the fact that a man would come to the holy Prophet (s.a.) and ask a question and would give him an answer and then he would answer that would abrogate the previous answer. Thus, Ahadith abrogated other Ahadith.”
Reference: Usul-al-Kafi; Ch. 21, H. 3