The Quran is considered like the backbone of Islam although the bulk of the religion is made from the sunna, or Mohammed’s traditions, which is based on his hadiths or sayings and considered second to the Quran in its importance. Practicing Islam is impossible without the sunna, because the Quran doesn’t explain anything about the Islamic rituals or sharia and refers Muslims to take Mohammed’s example, which only comes through his hadiths (Q.59:7).
It is frustrating that whenever ‘intellectual’ Muslims are engaged in debates on Islam, they quickly distance themselves from those hadiths that tend to implicate their religion unfavourably, no matter how authentic those hadiths are. Denying a hadith has become a defence-tactic by Muslim apologists in their effort to maintain the integrity of Islam. Their logic is that Islam doesn’t fall by the loss of one hadith or two, because Islam is kept up by the Quran. On the other hand, those Muslims are not ashamed to quote other hadiths, no matter how unauthentic they are, to boost their argument in favor of Islam. However, an overwhelming majority of Muslims remain strong believers in both the Quran and hadith, which they rightly consider to complement each other. The main stream Muslims consider those, who deny the hadith, as infidels, who would eventually deny the Quran as well. In many countries, your life will be as endangered by rejecting the hadith as by rejecting the Quran.
Behind the declared reason for denying the hadith lies the undeclared, but true, reason. The hadiths come in detailed language and with several narrations that support each other, which leaves little room for Islamists to take recourse of word-game or manipulation of meanings. On the other hand, the Quran comes in a vague, abridged and self-contradicting format that leaves room for twisting the language, as well as meanings, of its words. The Quran is covered with a thick layer of haze; some Muslims use this lack of clarity to argue and claim they can see a picture different from that of its critics.
How authentic is the hadith?
There are different collections of hadiths that Muslims consider to be the most authentic; the most well-known collections are Sahih al Bukhari and Sahih Muslim. Other collections include Al Nissaey, Al Tirmithy, Ibn Dauod and Ibn Maja. Together, these six collections are called the authentic six, the Sahih Sitta.
The ‘science of hadith’ (Ilmul Hadith) is a well-known and prestigious speciality in all Islamic university. It teaches how those scholars managed to gather their collections and how they undertook arduous journeys, travelling the Islamic world, to accomplish their objective. The methodology they used, considering its time, was exemplary. They studied each hadith in details; its text and its chain of narrations and classified them into grades according to their authenticity. Even by today’s standards, their scholarship and dedication to objectivity was amazing. Most of the two hundred thousand or so hadiths that were subjected to their thorough assessment were rejected and only a few thousands made it to their Sahih (authentic) books. Their objectivity meant that many ‘good looking’ hadiths had to be rejected while others, not so good looking ones, had to be included because of the evidence available in their support. If Muslims can be proud of anything at all, objective academic approach, adopted by those scholars in collecting the hadiths, would top the list.
Those early Muslim scholars, like Al Bukhari and Muslim, were no ordinary people; they were well-informed highly educated and intelligent, and most of all dedicated to honest research to find the true life of the prophet. In short, they were the geniuses of their time. It is laughable that some modern Muslims, with questionable knowledge and education, dare to dismiss the brilliant works of those illustrious scholars as faulty, just because they don’t to go well with their biased opinions.
How authentic is the Quran?
Q.2: 106. Any verse We abrogate or cause to be forgotten, We substitute with something better or similar. Don’t you know that Allah can do anything?
The above verse is a short answer to those, who claim the Quran was preserved in a tablet in heaven. The verse is a clear admission that the Quran contains contradicting (Muslims call it abrogated) verses, as well as verses that have been completely forgotten! But one need not worry; Allah was capable of bringing similar verses or even of replacing them with better ones!
Unlike the hadith, the collection of the Quran was politically motivated and employed no methodology or high standard of scrutiny that characterized the collection of hadiths. The vulnerability of the Quran lies in the fact that the presence of only one error, say a misplaced word or letter, is a good enough proof that the entire book is a hoax.
It is essential in Islam to believe that the Quran is the preserved word of Allah. Therefore, it has an unquestionable authenticity. Indeed, Muslims never question the authenticity of the Quran, which is where their problem lies. They believe that the reason why Islam came to existence was the distortion that entered the previous Holy Scriptures. In other words, Muslims believe that Allah revealed the Quran with the determination to preserve it. With that in mind, one would expect Allah to have employed extraordinary measures to preserve what is supposed to be the most important and final divine document to mankind. But He didn’t! In fact, all the circumstances and ways the Quran was revealed, and it was handled by Allah’s beloved prophet, it was an ideal setting for the Quran to be corrupted if not lost, which it did.
1. The Quran was revealed to Mohammed, who was, as Muslims insist, illiterate and, therefore, unable to verify the accuracy of the scripts written for him by some volunteering scribes of no high standard. Trusting Mohammed with the Quran is a greater blunder than trusting an illiterate person to edit New York Times. With a document as important as the Quran, it would not be enough just to assume that the scribes were honest and trustworthy, especially that at least one of them, Abdulla Ibn Abi Al Sarh, admitted that he regularly made changes to the text of the Quran without Mohammed even noticing! 
2. Muslims claim that the Quran was completely written during Mohammed’s life time, but there is no acceptable evidence to support such a claim. It is logical to believe that the Quran was not properly written in the first thirteen years of Islam, while Mohammed was still in Mecca because he simply didn’t have the resources to do it. One would expect that writing down the Quran might have been Mohammed’s first priority after he assumed power in Medina, but he was too busy in wars to think of it.
After establishing his Islamic state in Medina, Mohammed could have ordered a formal recording, indexing and safe-keeping of the most important document of Islam. Even he could have stamped it because he owned a stamp. But Mohammed did nothing of that sort, which indicates that he never took the matter seriously. In fact, there are reasons to believe that Mohammed actually benefitted from that chaotic state of the Quran. An undocumented Quran gave Mohammed the freedom to change his mind or contradict himself and get away with it, claiming that the earlier memorized verses had been forgotten or faded away from memory. Recording the ‘revealed’ verses in Medina took place in a casual manner; the job was carried out by whoever was available from those volunteering scribes. Some verses were written by more than one scribe, causing confusion, while others may never had the chance to be written at all, causing even more confusion.
3. The Quran was revealed, in the seventh century, in Arabic, a language that had not yet a well-developed script. Many Arabic words with different meanings shared the same script. The Arabs solved this problem by adding different numbers of dots to the letters that share the same appearance, but that solution came years after Mohammed’s death. As an example, the Arabic word harb, which means war, has the same appearance like a dozen other words with completely different meanings, like these: حرب.خرب.حزب.جرب.حزن.جزت.حزت.خزن(The above words mean: war, damaged, party, tried, sadness, rewarded, caused pain, stored)If you strip the letters from their dots, all the words look exactly the same, and it was left to the readers’ commonsense and intelligence to work out which particular word was meant by a particular script.
Ideally, for a better preservation of the Quran, Allah should have educated Mohammed and created the dots before ‘revealing’ the Quran.
The Arabs claim that their language is a superior language, hence chosen by Allah as His official means of communication. Other Muslims agree with that claim and praise the language as the most beautiful, without even speaking or understanding the language. The truth is that Arabic is a complicated language that is difficult to develop especially that it is now attached to the Quran, which is holding it back.
Even in our time, and after the ‘invention’ of the dots, reading an Arabic text is still a guess work. Arabic books and newspapers are printed without the diacritical marks to reduce the clutter around the words. The diacritical marks were ‘invented’ over a century after the dots. Without the diacritical marks, the fourth word in the above example, Jarab, could be read as follows: Jarraba=tried, Jurriba=has been tried, Jarab=plague, Jurub= suffering of plague!
4. Writing technology in Arabia was very primitive and employed poor quality and perishable writing materials like palm leaves and bones.
Although we read the Islamic history only from it’s heavily biased Islamic sources, but we frequently stumble upon some historical facts like the following:
Ibn Massoud was renowned among Mohammed’s companions as the most notable in his knowledge of the Quran; it is claimed that he recorded his own copy which he kept with him. Ibn Massoud’s copy of the Quran was significantly different from the official copy of Uthman, which he refused to recognize (2). Some verses were lost, even the ones kept in Mohammed’s own house! Aysha admitted that she used to keep the “stoning verse” under her bed until it was eaten by a goat! 
Al-Hajaj Ibn Youssef Al-Thakafi, the ruthless ruler of Iraq during the Umayyad dynasty, made many changes to the official Quran many years after Uthman. 
Political corruption, power struggle and instability characterised the period of Uthman’s rule. It was in such an unhealthy political climate when Uthman ordered the compilation of the Quran.
Uthman sent four copies of his official Quran to the various regions of the expanding Islamic state and kept one copy in Medina. None of those copies seem to have survived. There is no evidence that any of the old copies of the Quran, that we have today, dates back to Uthman’s time. The oldest copy available, which is the manuscripts of Sana’a (Yemen), dates back to many decades after the time of Uthman and contains significant differences from the current Othmanic version of the Quran. 
Many Muslim scholars are aware of the weakness of the argument that the Quran was documented during Mohammed’s time. They claim that the Quran was preserved mainly in Muslims’ chests, the written documentation was only a backup! Unfortunately for them, making such a claim is like digging the grave for the Quran, because the main reason behind writing a formal copy of the Quran, and burning all the others, was to stop the disagreements between Muslims. The Quranic verses that were preserved in the Muslims’ chests were so different that they accused each other with kufr (unbelieving)!
The Quran is probably the least authentic document in Islam as evidenced from the state of confusion and disagreements that prevailed amongst early Muslims. The early Muslims disagreed on what constituted part of the Quran and what didn’t. Ibn Massoud’s copy of the Quran included two chapters less than Uthman’s copy, because he did not believe the last two chapters were actually Quranic chapters. Others reported that Surat Tauba (Chapter Nine, which contains 129 verses) used to be as long as Surat Bakara (Chapter Two, which contains 286 verses) before the verses went missing . Abdullah Ibn Umar reportedly said, 'Let none of you say, "I have got the whole of the Qur'an." How does he know what all of it is? Much of the Quran has gone’. Let him say instead, I have got what has survived (6). The enormous amounts of repetitions and contradictions could be an indication of some degree of duplication and manipulation of the original text.
According to the existing Quran, the penalty for adultery is only described in verses Q. 24:2 (flogging hundred lashes) and Q4: 15 (house detention), and nowhere in the Quran is stoning mentioned. However, Muslims agreed for fourteen hundreds years that the penalty of adultery is stoning to death, because the verse, which abrogated the above two verses, was there and remains effective in its orders, hukman, even though its words were cancelled, kawlan. We can add this logic to the pile of other bizarre justifications, used by Muslims, to understand the Quran. However, we have the right to ask: why Allah keeps in the Quran the obsolete verses and omits the valid ones?
With thanks from Islam Watch