The following verses from the Old Testament show how seriously God takes the preservation of His Word. He will not allow it to be corrupted. The evidence that follows shows how history bears this out.
A. Manuscript Evidence
There are many Hebrew Old Testament manuscripts predating Muhammad. (6)
Though manuscripts have not yet been found that date back to the times of Moses and the Old Testament prophets, manuscripts do exist from a very ancient date and these have the same contents of the Old Testament we possess today. The textual variants in them do not alter one doctrine but are mainly scribal errors consisting in items like misspelled words, transposed words, and portions copied twice.
B. Lists of Old Testament books predating Muhammad lists.
The following people and events pre-dating Muhammad gave lists of the books making up the Old Testament:
These main lists (there are other personal lists in the writings of various early church fathers) show that the Jews were very sure of the contents of the Word of God they had received. They all list the same books that are in the present Old Testament. The Christians accepted the same Hebrew Scriptures as the Word of God also. There was no disagreement between them as to which books were in the Old Testament.
C. Evidence from within the Old Testament as to its own transmission
Presented here are Scripture quotations which show that the preserving of manuscripts goes back to Moses. (All quotations are from the New International Version of the Bible)
The Israelites preserved their scriptures throughout their history. The oldest Old Testament manuscripts date back to the 400 year period preceding Jesus' birth, the period of time between Ezra the scribe and Jesus. During this period the Old Testament Scriptures were to be found wherever Jews were found, especially in Egypt, Palestine, and Babylonia.
D. Jesus' testimony to the Old Testament's authenticity
Most of Jesus' public ministry was spent preaching and explaining the Old Testament. He knew the whole of the Old Testament intimately and quoted from it readily. In every instance he upheld the Old Testament as we have it today as the Word of God without error or corruption. He only spoke of it in ways that assumed its total authority and truth, and he held others accountable to it. Jesus also submitted himself to it unreservedly and in totality. He lived according to it strictly, and He even died according to its words, quoting it three times while on the cross, and dying in the precise manner it predicted the Messiah would die (Isaiah 53 and Psalm 22). There is no evidence that Jesus held any other book given to the Jews to be the word of God and no evidence he saw any of the Old Testament as being corrupt.
E. Attempts by the Jews to corrupt their Scriptures
The only such attempt known to this writer is discussed in Edmund Wilson's book, The Scrolls From the Dead Sea. This scholar documents a Greek version of the Old Testament that some Jews made to disagree with the Septuagint. The passages they altered concerned major prophecies of the Messiah and were changed to make it more difficult to identify Jesus as the Messiah. They did this because Christians were using the Septuagint with great success to show that Jesus really was the promised Messiah.(10) Note that this was a failed attempt! First, it did not change the text of the Hebrew Scriptures but was a biased translation into Greek. Second, this version was not adopted by mainstream Judaism even though they too rejected Christ. Instead, this translation dropped off into obscurity. Third, note that it involved only verses concerning Jesus, not whole books or sections of the Old Testament. And fourth, note the motive of the changes: to deny recognition of Jesus as the predicted Messiah of the Old Testament. This attempt shows how God, the great majority of the Jews, and the Christians protected the authentic Word of God given to them.
F. Conclusions
The Old Testament in the Bible as is available today is the same as was available in and before Jesus' time. This Old Testament is also considered by Jews to be their Holy Scriptures. There is no evidence that any other book except the version mentioned above was ever regarded as the Scriptures of the Jews. The Jews and the Christians protected the Old Testament Scriptures from corruption and any isolated attempts to corrupt it did not succeed. Therefore the present Old Testament is the uncorrupted Scripture of the Jews that was available before and up to the time of Muhammad.