Here is a comparison list of New Testament Quotes used by the Apostles. The texts in blue are from the Greek Septuagint, and the text in red are from the Masoretic Text used in all modern day English Bibles (except the Greek Orthodox Study Bible).
Hebrews 10:5 (Quoted from Psalm 40:6)
Therefore, when He comes into the world, He says, 'Sacrifices and Offerings you did not desire, but a Body thou hast prepared for me….'
Greek Septuagint: Sacrifice and offering Thou didst not; but a body Thous has prepared Me…
Masoretic Text: Sacrifice and Offering Thou did not desire; mine ears hast Thou opened…
As you can clearly see, this was an obvious alteration made by false Jews, sometime between the 2nd to 4rth centuries; exact time is uncertain, but we do know that Jews of that age fought against Christians using the Greek Septuagint. Thus in this case, the New Testament source used by the Apostles (specifically the author of Hebrews, probably St. Paul) relied on the Greek Septuagint.
Hebrews 1:6 (Quoted from Deuteronomy 32:43)
Hebrews 1:6 ( KJV New Testament)
And again, when he bringeth in the firstbegotten into the world, he saith, And let all the angels of God worship him.
Greek Septuagint: Deuteronomy 32:43
Rejoice, ye heavens, with him, and let all the angels of God worship him...
The Masoretic Text deletes this half of the verse all-together! It does not exist anywhere else in the Old Testament! Such utter Blasphemy!
Matthew 12:21 (Quoted from Isaiah 42:4)
And in his name shall the Gentiles trust.
Greek Septuagint: Isaiah 42:4
He shall shine out, and shall not be discouraged, until he has set judgment on the earth: and in his name shall the Gentiles trust.
Masoretic Text: Isaiah 42:4
He shall not fail nor be discouraged, till he have set judgment in the earth: and the isles shall wait for his law.
The "isles" was a Jewish symbol or metaphor used to represent Israel. [note: This proves my theory that ancient Jews understood "islands" to represent Israel, while the "seas" represent Gentiles. This thus supports my position on Revelation: Land is Israel, Seas are Nations] The Jews altered this verse to show that God would send judgment upon the world, but the land of Israel (isles) would wait patiently for God. They (Jews) did not like any mention of God bringing in Gentiles to God's kingdom. We've seen this attitude displayed by even some of the Apostles in the book of Acts, when Peter had the dream of the "unclean things/animals". The "unclean animals or swine" represents fellowship with foreigners, which according to Jewish custom, was forbidden. But Jesus showed that His sacrifice and blood would make it possible for Jews and Gentiles to worship Him within a single kingdom; the Church. Apparently, the Jews rejected this idea, and altered certain verses used against them by 1st through 4rth century Christians. Their solution? Change the text to teach their descendants to maintain the Mosaic traditions of the Old Testament. Unfortunately, St. Jerome made a terrible mistake by translating the Old Testament using text handed down to him from these false Jews. This was the Latin Vulgate.
In conclusion, while there are more examples of obvious tampering, this was enough to convince me that the Old Testament used in current English Bibles is based on the altered copies of the Masoretic Text. I know this hampers the BibleWheel vision due to the different ordering/numbering of Old Testament books, especially Isaiah and Psalm, but the truth should be clear; the Greek Septuagint is more reliable than the Masoretic Text of the Old Testament, and should thus be avoided.
I believe that all Bible Production companies should issue an emergency recall of all current English Bibles to be replaced with the Greek Septuagint translated into English immediately. I've considered writing letters to certain publisher companies, but haven't yet decided how I would pursue this issue. Thankfully, I'm seeing more scholarly work on this subject within a few Bible colleges.
We cannot trust the Masoretic Text. And while the Greek Septuagint might have a few errors itself, it at least completely satisfies the quotes used in the New Testament, where as the Masoretic Text is missing a great percentage of New Testament quotes.