Question: "How does the preservation of the Qur'an compare to the preservation of the Bible?"
Answer: The Qur’an has no manuscript support because of the way it was compiled into written form. Islam’s primary holy text was not a “text” at all until decades after the death of Muhammad. At that time, oral remembrances and assorted notes were edited and converted into print by one of his successors. All other written records were purposefully destroyed. In contrast, the New Testament was copied and dispersed in written form immediately, without centralized control. By the time authority figures had interest in it, the Bible had been distributed for centuries. By then, it was impossible to edit without making the changes blatantly obvious.
Muhammad was illiterate; this is something Muslims often point to as evidence that his revelations were divine. For more than twenty years, he proclaimed individual statements supposedly given to him by Allah. When Muhammad died in AD 632, there was no written version of the Qur’an. There were random verses recorded on leaves and bones, but the words were primarily kept in oral form by men who had memorized portions of Muhammad’s declarations.
After Muhammad, the Islamic Empire transitioned into a series of new leaders, known as caliphs. It also fell into arguing and infighting. Some disagreements involved Muslims of different cities reciting variant versions of the Qur’an’s verses. Battles resulted in the deaths of many who had memorized portions of those words. Approximately twenty years after Muhammad’s death, Caliph Uthman ordered Muhammad’s associate, Zayd ibn Thabit, to collect whatever information was available and compile an “official” version of the Qur’an. This was recorded in written form.
When this work was complete, Uthman sent five copies to various locations across the Islamic Empire. He ordered every other written record of the Qur’an to be burnt. All other versions and records of the Quranic statements of Muhammad—every scrap, leaf, bone, and fragment—was destroyed. The only version of the Qur’an that remained was the one that Uthman and Zayd ibn Thabit had compiled.
In contrast, the New Testament was written within years of Jesus’ crucifixion and immediately copied and distributed. Even today, we have thousands of copies of those texts. These records not only show that the copying process was faithfully done, but it also makes any scribal errors or other variants obvious. For the first three centuries of the church, faith in Christ was effectively illegal. There was no connection whatsoever between Christian Scripture and government authority. By the time Constantine de-criminalized Christianity, the written text of the Bible was spread far and wide. This made any attempts at editing impossible.
In summary, the Qur’an was entirely oral for decades; it was only compiled into written form when disagreements arose about its contents. The text version was made by the ruling powers of the day, who ordered all of the fragmentary and disparate writings destroyed. All that remained of the Qur’an, from that moment on, was whatever words the authority figures wanted. In stark contrast, the Bible was copied and distributed in written form immediately, without any central oversight or authoritarian decree; further, the Bible quickly spread beyond the reach of any possible editor.
The history of the Qur’an gives us no confidence that it contains the original words of Muhammad. At best, Islam can claim the modern Qur’an to be the same words approved by the third Islamic caliph after a process of controlled editing. In contrast, history says the Bible was preserved explicitly as a result of its uncontrolled copying process, which made the Bible immune to any attempts at editing or redaction.