I started a thread comparing the Septuagint to the Masoretic text.
It is here:
https://www.jehovahs-witness.com/topic/5665236409384960/comparing-septuagint-masoretic-text
For those who do not know what the Septuagint and the Masoretic text are, here's an introduction on Wikipedia:
https://en.wikipedia.org/wiki/Septuagint
https://en.wikipedia.org/wiki/Masoretic_Text
I think that, more than anything else, the fact that the Septuagint and the Masoretic text are so different, is what made me stop believing in the Bible.
And more than anything else, the most striking differences between the Septuagint and the Masoretic text have to be the genealogies of Genesis 5.
The genealogies of Genesis 5 are CRUCIAL to the Jehovah's Witnesses, the Adventists, and many other religions that place an emphasis on time prophecy.
Why is that?
Because they try to make out when the "end of the world" happens based on the 6000 years of human existence, they HAVE to use Genesis 5. And, if the numbers in Genesis 5 in the Bible most people in the Western world use are wrong, then the time to creation is wrong, and then the "end of the world date" is wrong.
So, what are the differences?
The account tells the ages in this format:
X person lived for Y years. Then he had a son. Then he lived for Z more years, so his total lifespan was A years.
Let's start with Adam in the Masoretic Text (New World Translation, 1984 version):
(Genesis 5:3-5) 3 And Adam lived on for a hundred and thirty years. Then he became father to a son in his likeness, in his image, and called his name Seth. 4 And the days of Adam after his fathering Seth came to be eight hundred years. Meanwhile he became father to sons and daughters. 5 So all the days of Adam that he lived amounted to nine hundred and thirty years and he died.
So we have:
Adam, 130 + 800 = 930.
What does the Septuagint say?
Genesis 5:3-5, NETS:
Now Adam lived two hundred thirty years and became a father, according to his form and according to his image and named his name Seth. And the days of Adam after he became the father of Seth amounted to seven hundred years, and he had sons and daughters. And all the days of Adam, that he lived, amounted to nine hundred thirty years, and he died.
Adam, 230 + 700 = 930.
You might say at this moment, "so what? At the end of the day, it says that Adam lived for the same amount of time." That is true, but the most important number in this format is the first one. There are 100 years of difference between Adam becoming father to Seth in the MT and the LXX.
What about the rest of the people in Genesis 5?
You can see them here:
https://en.wikipedia.org/wiki/Genealogies_of_Genesis#Genesis_numbers
The first number in the list in Genesis is added up with all the generations (and then added with the same formula in Genesis 11), and we get:
The MT gives 1946 years from the creation of Adam until the birth of Abraham.
The LXX gives 3312 years from the creation of Adam until the birth of Abraham.
QUITE THE DIFFERENCE!
This would make the Jehovah's Witnesse's "1975", when supposedly 6000 years of human existence ended, in 609 A.D.
We would be in the year 7,407 after creation if we were to base ourselves on the LXX instead of the MT.
This, just this, is enough for some (me included) to stop believing that the Bible is true and inerrant.