I have seen "evidence" that we know with a great degree of certainty and accuracy what the original bible said. This is to say, we know what the original authors wrote. I'm not sure how accurate these claims are as they seem to come from biased sources. Here are a few:

https://www.youtube.com/watch?v=cWxwfFNyVws

https://carm.org/new-testament-corrupted

The short answer is no [the bible was not corrupted]. To answer this question in more detail, let me give you some background. The New Testament is an ancient book. During ancient times, there were no Xerox copy machines, and the way the Bible was preserved was through hand by hand copying. As a result of this copying process, errors would occur by accident or intention. However, these errors in the text do not affect any major Christian doctrine such as the Trinity, Deity of Christ, salvation by faith alone, etc. Unfortunately, we do not have any original copies of any of the books of the New Testament. In other words, we do not have “the original manuscript copy” of Paul’s Epistle to the Romans or an original copy of the Gospel of Matthew, etc.

http://www.essentialbibleblog.com/2013/03/top-10-reasons-bible-is-true.html

The first five points at least...

To be clear I'm not asking if the events talked about in the bible are true. I'm asking do we know the words (or decidedly synonym words) used by the original authors?

I have seen "evidence" that we know with a great degree of certainty and accuracy what the original New Testament bible said. This is to say, we know what the original authors wrote. I'm not sure how accurate these claims are as they seem to come from biased sources. Here are a few:

• YouTube Video: Is the Bible Reliable?

• Christian Apologetics and Research Ministry: Has the New Testament been corrupted?

The short answer is no [the bible was not corrupted]. To answer this question in more detail, let me give you some background. The New Testament is an ancient book. During ancient times, there were no Xerox copy machines, and the way the Bible was preserved was through hand by hand copying. As a result of this copying process, errors would occur by accident or intention. However, these errors in the text do not affect any major Christian doctrine such as the Trinity, Deity of Christ, salvation by faith alone, etc. Unfortunately, we do not have any original copies of any of the books of the New Testament. In other words, we do not have “the original manuscript copy” of Paul’s Epistle to the Romans or an original copy of the Gospel of Matthew, etc.

• Top 10 reasons the bible is True

There are way more copies of the biblical manuscripts, with remarkable consistency between them, than there are for any of the classics like Plato, Aristotle and Socrates. "There is no body of ancient literature in the world which enjoys such a wealth of good textual attestation as the New Testament." F.F. Bruce, The New Testament Documents: Are They Reliable?

To be clear I'm not asking if the events talked about in the bible are true. I'm asking: Do we know the words used by the original authors of the New Testament?