Appearance of Forged Ahadith It is a most tragic fact that people had started attributing forged traditions to the holy Prophet (peace be upon him & his progeny) even during his life time. The Prophet had to warn the Muslims of this fitnah in these words: 
"Surely there are many who forge lie against me, and their number is sure to increase; whoever intentionally tells a lie against me should prepare his abode in the Fire. Therefore, whenever a hadith is narrated to you, put it (for testing) before the Book of Allah and my (established) sunnah, and whatever conforms with the Book of Allah, take it; and what goes against the Book of Allah and my sunnah, reject it." [8]
This well-known hadith is very important and I request you to keep it in mind. We should realize that the Prophet has appointed the Qur'an as the standard for judging a hadith, not that the Qur'an is to be judged by ahadith.
Amiru 'l-mu'minin 'Ali (a.s.) was asked as to why there were differences in the traditions attributed to the Prophet. In reply, he said, "Certainly what is current among the people is both right and wrong, true and false, repealing and repealed, general and particular, definite and indefinite, exact and surmised. Even during the Prophet's days false sayings had been attributed to him, so much so that he had to say during his sermon that 'Whoever attributes falsehood to me makes his abode in Hell'. Those who relate traditions are of four categories, no more."
Then the Imam said that the first category was of the lying hypocrites: "The hypocrite is a person who makes a show of faith and adopts the appearance of a Muslim; he does not hesitate in sinning nor does he keep aloof from vice; he willfully attributes false sayings to the Messenger of Allah-may Allah bless him and his progeny. If people knew that he was a hypocrite and a liar, they would not accept anything from him and would not confirm what he says. But they say that he is a companion of the Prophet, has met him, heard (his sayings) from him and acquired (knowledge) from him. They, therefore, accept what he says. Allah too had warned you well about the hypocrites and described them fully to you. They have continued after the holy Prophet. [9]
However, the situation became worse after the martyrdom of Imam 'Ali (a.s.), when amir Mu'awiyah established what may be called the first propaganda department in the world. It is not the place to go into sordid details. Those who wish to know more may see the Sharh Nahji 'l-Balaghah of Ibn Abi 'l-Hadid al-Mu'tazili, who quotes verbatim from Kitabu 'l-Ahdath of Abu 'l-Hasan 'Ali ibn Muhammad ibn Abi Sayf al-Mada'ini, showing how this department developed stage by stage until the ahadith fabricated by them permeated the whole Muslim world; these 'ahadith were taught to the children in maktabs like the Qur'an. He mentions how the malady had affected all groups and especially those who showed piety, recited the Qur'an, and were thought to be very God-fearing. They used to forge ahadith to seek favours with the rulers. Finally these 'ahadith' reached those who were really religious-minded and did not approve of lie and false attribution. They accepted the traditions as genuine and transmitted them thinking that they were genuine sayings of the Prophet. [10]
Four narrators of ahadith were the core of that department: Abu Hurayrah, Amr bin al-'As, al-Mughirah bin Shu'bah (all from the sahabah, companions) and 'Urwah bin az-Zubayr (from the tabi'in, disciples of the companions). [11] But there were hundreds of free-lancers who sold their religion for worldly gains. One incident is given here as an example.
Mu'awiyah once offered Samurah ibn Jundab one hundred thousand dirhams if he would narrate that the verse 204-205 of the second chapter of the Qur'an were revealed concerning 'Ali ibn Abi Talib, and that the verse 207 was revealed in praise of Ibn Muljam (the assassin of 'Ali).
The verses are as follows: "And among men is he whose speech about the life of this world causes you to wonder, and he calls on Allah to witness as to what is in his heart; yet he is the most violent of adversaries. And when he turns back, he runs along in the land that he may cause mischief in it and destroy the tilth and the stock, and Allah does not love mischief-making." These were to be attributed to 'Ali.
And the verse 207 which says "And among men is he who sells himself to seek the pleasure of Allah; and Allah is affectionate to the servants" was to be attached to Ibn Muljam.
However, Samurah did not agree. The price was raised to two hundred thousand and then to three hundred thousand, but to no avail. Finally Mu'awiyah offered him four hundred thousand dirhams, and Samurah agreed and narrated a 'hadith' to that effect. [12]
[8] Shaykh 'Abbas al Qummi, Safinatu 'l-Bihar, vol. 2 p. 474. Countless ahadith to this effect may be seen in the books of both sects, including Sahih al-Bukhari, vol. 1 (kitabu l- ilm: bab ithm man kadhiba 'ala n-Nabi ) p. 38.
[9] Nahju 'l-Balaghah (translated by S. Ali Raza), vol. 2 (Tehran: WOFIS, 1987), pp. 453-545.
[10] Ibn Abi l-Hadid, Sharh Nahji 'l-Balaghah, vol. 11 (Cairo: Daru 'l-Ihyai 'l-Kutubi 'l-Arabiyyah) pp. 446.
[11] Ibid, vol. 4. p. 63.
[12] Ibid, vol. 4. p. 73.
Unfortunately, as mentioned above, even supposedly good people indulged in this forgery. Abu Ismah, Faraj bin Abi Maryam al-Marwazi was asked: "From where have you got all these traditions narrated through 'Ikrimah, from Ibn 'Abbas, from the Prophet, describing the reward of reciting each and every surah (chapter) of the Qur'an?" He said, "I found people interested only in the fiqh of Abu Hanifah and maghazi of Ibn Ishaq; therefore, I forged these ahadith 'for the pleasure of God' to bring them back to the Qur'an." [13]Once forgery of ahadith became the norm of the Muslim academic world, the atheists, zanadiqah, and hypocrites exploited it to their full advantage. They introduced thousands of ahadith all supposed to come down through well-known companions of the Prophet to destroy the fabric of Islam, to weaken its foundation and bring down the whole edifice. For example, the well-known atheist, 'Abdu 'l-Karim ibn Abi 'l-'Awja', was sentenced to death by the governor of Kufa. When he was about to be killed, he said, "Well, even if you kill me, I have fabricated four thousand ahadith turning halal into haram and haram into halal. By God, I have made you to break fast on the day of fasting and to fast on the day of 'Id." [14]
But this plan could not succeed unless the Muslims were made to believe that the Qur'an was not collected during the Prophet's time, but was later collected piecemeal from papers, shreds of pottery and bones, some twenty three years after the Prophet's death.
They understood very well the psychology of various groups of the Muslims, and they presented their anti-Qur'anic themes disguised as a distinction (fazilat) of the sahabah (the companions) and the Imams of Ahlu 'l-bayt in order to mislead the Sunnis or the Shi'as, respectively. The poison was administered in sherbet and it was unhesitatingly swallowed.
The distinction of collecting the Qur'an was given to Hazrat Abu Bakr or Hazrat 'Uthman. Every fabricator has used his own imagination and it resulted in a lot of traditions contradictory to each other.
Sayyid al-Khu'i has reviewed in detail all the traditions concerning the later days collection of the Qur'an, and has come to the conclusion that the third Caliph had not "collected" the Qur'an. What he had done was to unite the Muslims on the recital which was followed in Medina, and forbid all other recitals, which had sprung up here and there. Those interested to study this in depth should refer to his al-Bayan from p. 187 to p. 278.
However, once this story of later days collection was established it was easy to circulate ahadith showing that a lot of verses, even some surahs, were lost and could not be found at the time when Hazrat Abu Bakr and/or Hazrat 'Uthman wanted to collect it in Book form. They attributed such statements to great companions and wives of the holy Prophet (peace be upon him & his progeny).
Mesmerized by those traditions, the Muslims forgot that Allah Himself is the Protector of His Book and that the Prophet had appointed the Qur'an as the standard to test the authenticity of traditions. They turned the table and began testing the authenticity of the Qur'an through those alleged ahadith!
[13] al Bayan, p. 37: Ahmad Amin, Fajru 'l-Islam, p. 215.
[14] at-Tabari, Tarikh at-Tabari, vol. 6 (Beirut: Mu'assasatu l-A'lami) p. 299: Ibn al-Athir, Tarikh al-Kamil, vol. 5 (Daru l-Kutubi l-Arabi. 1985) p. 39.