Question: The enemies of the Sahabah say, "If a hadith is narrated from Ali, Imam Hasan, Imam Husayn, Salman, Abu Dhar, Miqdad, or Ammar bin Yasir, it is reliable. The ones other than these are not trustworthy because the Prophet said, 'The ahadith that are narrated from me can be made known by four people. There is not the fifth one. The others are hypocrites.' The Muslims chose those hypocrites as their leaders. None of the Sahabah could ask the Messenger of Allah questions because asking him questions was prohibited by ayah. Only Hadrat Ali could ask."
ANSWER
"Of the four caliphs (i.e. Abu Bakr, ’Umar, ’Uthman, and Ali ‘radiy-Allahu ’anhum’), Hadrat Ali occupies the first place in point of hadith-i sharifs and knowledge of tafsir that the scholars of Ahl as-Sunnah wa'l Jama'ah reported on the authority of them each. This is a natural concomitant of the fact that he outlived the other three caliphs. Because Hadrat Abu Bakr was the earliest believer of them all and spent all his time spreading Islam’s rules and principles and solving Muslims’ problems, fewest traditions have reached us through him. For this reason, most of the scholars of Ahl as-Sunnah wa'l Jama'ah received their religious information from Hadrat Ali. Hadrat Ali used to say: “Ask me whatever you like. I know whether each ayah came down at night or during the day, during a battle or in peace-time, on a plain or in the mountains. I know reasons for the revelation of each ayah. I asked [the Messenger of Allah] the meaning of each ayah, learned it, and memorized it. Ask me and I shall tell you.” The scholars of Ahl as-Sunnah wa'l Jama'ah acquired their knowledge regarding tafsir and ahadith not only from Imam Ali, from Hadrat Hasan and Husayn, from Salman and from Abu Dhar (radiy-Allahu ’anhum), but also from all the other Sahabah because they were all exalted, just, and trustworthy people" (Mawduat-ul-Ulum).

"The Sahabah were many in number. There were 10,000 Sahabah by the time Mecca was conquered, 70,000 Sahabah during the Battle of Tabuk, and 90,000 during the Farewell Pilgrimage, and more than 124,000 when the Messenger of Allah died" (Mawahib al-Ladunniyyah).

"There were 124,000 Sahabah when the Messenger of Allah died. All of them were just and trustworthy" (Anwar li-a'mal al-abrar).

It is haram and a grave sin to swear at the Sahabah because all of the 124,000 Sahabah were a mujtahid each. It was wajib on them to act on their own ijtihads at those battles, and they did so.

Hadrat Imam-i Ghazali states:
"It is haram to describe, in oral or written forms, the martyrdoms of Imam Hasan and Imam Husayn or the battles that took place among the Sahabah. Indeed, doing so may imply animadversion and provoke enmity against any one of them. Conveying the Islamic religion to posterity was their common service, to which each and every one of them had contributions. To censure any one of them, therefore, means to censure Islam, which in effect means to demolish the religion. A mujtahid can act on any hadith. Every word of the Sahabah is a proof" (Rawdat-ul-Ulama).

Hadrat Imam A'zam said to his students:
“If you discover a statement made by any of the Sahabah that is disagreeable with my ijtihad, leave my word aside and follow the Sahabi’s statement.”

These facts show that the scholars of Ahl as-Sunnah wa'l Jama'ah took the words of the Ahl al-Bait as proof and hinged their knowledge on this base because the Ahl al-Bait and all the Sahabah always stated the same things, which were what they had heard from the Messenger of Allah ('alaihis-salam). Their disagreements based on ijtihad should not be construed as changing ayahs and ahadith.

After prophets, the highest of all humans is Hadrat Abu Bakr. As a favor and blessing from Allahu ta’ala, he had not worshipped idols even before he became a Muslim. After him, the highest of human beings is Hadrat 'Umar. After him, the highest of human beings is Hadrat ’Uthman, the treasure of favors and blessings and the source of modesty, faith, and spiritual knowledge. After him, the highest of human beings is Hadrat ’Ali, the possessor of astonishing superiorities and the Lion of Allahu ta’ala. The next highest ones of the Sahabah were al-’Asharat al-Mubashshara, the ten people blessed with the good news of [going to] Paradise. After them, the highest Muslims were the 313 Muslims who took part in the Battle of Badr. The next were the 700 Muslims who took part in the Holy Battle of Uhud. Next to them were the 1400 Muslims who took the oath of allegiance to the Messenger of Allah under the tree (Biat-ur-Ridwan). After them, the highest of all humans are the other Sahabah. All of them will be in Paradise. (Surah al-Hadid 10)

The Sahabah sacrificed their lives and property for the sake of the Messenger of Allah and assisted him. It is wajib on us to mention the name of any of them with veneration and love. It is never permissible to say words unbecoming their greatness. It is heresy to mention their names disrespectfully. One who loves the Messenger of Allah has to love all of his Companions.