“In the old days”, Scripture was written on sheepskin. It was fairly durable, but after 2 or 3 decades of use, it would wear out, and have to be recopied. Potentially there is a chance for error in this recopying.
The oldest complete Hebrew bible is in St. Petersburg, Russia, and dates to about 1010 A.D. There is another bible in Ethopia that is about a century older, but it is in Abyssinian, and was based on a Greek translation.
Near the Dead Sea, near an ancient community known as Qumran, are hundreds of caves. In the 1950’s a nomadic shepherd discovered in these caves a series of ancient sheepskins that are today called the Dead Sea Scrolls. These scrolls are portions of the Old Testament. Some books are complete, others are only fragmentary. But what makes them especially significant is that they date to about the time of Our Lord.
For decades, only a select group of scholars were allowed access to the Dead Sea Scrolls. This applied not only to the original scrolls, but also to copies of any kind.
In 1991, a “bootleg” (but accurate) copy of the complete Dead Sea Scrolls was released. Instantly, Bible scholars everywhere had access to a 2,000-year-old Old Tesrtament.
Not surprisingly, there are some differences between The Leningrad Codex (as the Russian bible is called) and the Dead Sea Scrolls. Surprisingly, there are no significant variances. There may be a few words changed here or there, but not in such a way as to distort the meaning of any doctrine.
Prior to the 1990’s there may have been speculation about the reliability of bible translations, but toay there is no doubt.