How does the written evidence of the Old Testament compare to the later written evidence in the New Testament?
There are a many good reasons to trust in the writings of the Old Testament, a few of which I will outline below:
Its claim as the word of God
The Old Testament claims itself to be the words of God many times, for example the phrase “the Lord says” and other variations appear 3808 times. Combine this with the claim within itself that the word of the prophet is equal to God’s word (“If anyone does not listen to my words that the prophet speaks in my name, I myself will call him to account.” Deuteronomy 18:19). There can be no uncertainly that the writers claim to be writing the words of God.
The historicity of events
The Old Testament stands as a description of history, and as such is there to be corroborated or contradicted by any archaeological evidence. Obviously, people argue for and against its presentation of history but as far as can be seen there is plenty of evidence for its accurate description of history. Individuals and Empires described in the Old Testament did exist and can be externally verified. Most notable is probably the Cyrus Cylinder which dates from around 539 BC and is housed in the British Museum. In this, the reign of Cyrus is declared and he tells of how he rebuilt temples in foreign cities and returned their inhabitants to the land from which they had been dispossessed. Both of these events occurred to the Jews and are described in 2 Chronicles.
Manuscript evidence
Perhaps the oldest extant documents of the Old testament are from the ‘Dead Sea Scrolls’ (which were discovered only very recently in 1947). Significant parts of the book of Isaiah which were found on this occasion match almost word for word with the same copies that we can read now in 2009 (minus very minor grammatical errors). The oldest fragment of these scrolls we have dates from around 200 BC and there are many other fragments and documents around which debate rages. At the very least we know that the Old Testament we have is the same as Jesus’ and combining this with the witness of archaeology leads me to have confidence in its authenticity. Certainly there is no obstruction to belief.
The witness of Jesus
Perhaps the most convincing evidence of the correctness of the Old Testament comes from Jesus himself. In Luke 24:44 Jesus says: “This is what I told you while I was still with you: Everything must be fulfilled that is written about me in the Law of Moses, the Prophets and the Psalms.”
In this Jesus is referring to the complete Old Testament beginning from Moses (Genesis) and ending with the prophets (Malachi). Subsequently we can learn that Jesus considered the Old Testament as the word of God and quoted from it regularly as the word of God.
In summary, history that is known of is in accordance with the Old Testament record and the manuscript evidence leads us with no reason to be concerned. Manuscript evidence is all relative with Caesar’s Gallic War going unquestioned with the oldest copy we have being written 1000 years after its original writing. Ultimately, if Jesus claims it to be God’s word and He is God we have no external reason not to believe this.