Mosaic authorship
    When dealing with the debate about whether Moses himself
    authored (when I say "authored" of course I mean that he was directly inspired
    by God), it is appropriate to begin with what the Pentateuch and the rest of the
    Scriptures have to say about the topic. 
    
    First, however, it is important to note that many verses which
    refer to the writings of Moses, particularly in the Pentateuch itself, only
    refer to small sections and therefore are themselves mostly irrelevant to the
    larger question of who authored the Pentateuch as a whole. For example, in Exo
    24:4 we read of Moses writing down all the words that God had just spoken, and
    in verse 7 we read of Moses taking this "book of the covenant" and reading it
    before all the people. Verses like this do not affirm the authorship of all five
    books of the Pentateuch and thus, while helpful in their own way with regard to
    other matters, do not deal with the question of the Documentary Hypothesis. But
    there are a number of references which do claim authorship by Moses for the
    "entire" Pentateuch (I enclose "entire" in quotation marks because it is
    understood that these claims do not deal with the extremely small number of
    isolated incidents where words that are in the Pentateuch today are probably not
    from Moses' own hand). 
    
    Before considering these references, there is one other matter
    that must be briefly attended to. According to the DH the books of Joshua,
    Judges-Ruth, Samuel, and Kings were written as part of the so-called
    "Deuteronomistic history" at the same time Deuteronomy was composed, namely
    during the early years of Josiah's reign. (Allowance is made by critical
    scholars for Kings being finished only a couple of decades later, perhaps by the
    same person (even Jeremiah or Baruch, according to some) or one of his close
    contemporaries.) Thus, when we consider references from these books, or from
    Chronicles, we generally must assume for the sake of argument that these claims
    carry no weight of proof, being claims only and not evidence. It is beyond the
    scope of this short study to examine the authorship of these post-Pentateuchal
    historical books, although (a) this issue is not nearly as serious in its
    implications as the issue of the authorship of the Pentateuch is, and (b) is
    largely determined by resolving the question of the authorship of the
    Pentateuch. 
    
    Having mentioned this brief caveat, let us turn our attention
    to the words in Jos 1:7-8, which refer to the Mosaic authorship of not just one
    small section, but rather of the entire "book of the law", which I take to refer
    to at least Exodus through Deuteronomy, if not Genesis as well. 
    
    Next we consider the record of Jos 8:30-35, which describes
    the altar that Joshua built to Yahweh Elohim of Israel upon Mount Ebal. V 31
    refers to building the altar of unhewn stones just as Moses had commanded. This
    commandment is recorded in Deu 27, in a section that critical scholars
    universally attribute to the original Deuteronomist of Josiah's day. Jos 8:32
    continues by mentioning the writing of the words of the law upon the stones of
    the altar, and vv 34 ,35 refer to Joshua reading all the words of the law of
    Moses to the people, including the blessings and the cursings. The blessings and
    the cursings are taken from Lev 26 and Deu 28, two sections which are also
    universally attributed by critical scholars to authors living hundreds of years
    after Moses. 
    
    Still in Joshua, we come to Jos 23:6, which is very similar to
    the Jos 1:7-8 reference cited above. Although as I have mentioned these
    references do not by themselves seem to deal directly with the question of the
    authorship of the book of Genesis, it is conceded by all that, were Exodus
    through Deuteronomy written by Moses, Genesis would have been too. Thus the
    claim for Mosaic authorship is effectively made here even though not directly
    made. 
    
    The next significant reference is in 1Ki 2:3, where it is
    recorded that as David charged his son Solomon, reference was made to the
    written Law of Moses. This clearly restates our basic claim. 
    
    The last two claims in the OT that we shall consider both
    concern events during the time of Joash, roughly eighty years before the time of
    Hezekiah, and thus at least that many years before the writing of either the P
    or D material, according to the critical scholars. In 2KI 14:5-6 we read of
    Joash refraining from executing the children of the murderers, and of holding
    this policy precisely because of the words of Moses recorded in Deu 24:16, part
    of the D material according to the DH. And in 2Ch 23 we read of Jehoiada making
    arrangements in accordance with what was written in the book of the Law of
    Moses. Significantly, these two references both claim to be verifiable in the
    exilic days, as reference is made to "the book of the chronicles of the kings of
    Israel" in 2Ki 14:15 and to "the story of the book of the kings" in 2Ch 24:27.
    These both refer to court documents that we know for certain must have existed,
    as demonstrated by the accuracy of the regnal lengths of the kings of Israel and
    Judah as shown by Edwin Thiele in his book "The Mysterious Numbers of the Hebrew
    Kings." If in fact these claims in both Kings and Chronicles are demonstrably
    false, the authors of these records must have been quite bold in not only these
    two verses, but in others as well, in challenging their contemporaries to
    examine the facts when the facts were demonstrably different. 
    
    In the NT we begin by considering the clear claims of Jesus
    with regard to the Mosaic authorship of all sections of the Pentateuch. In Mar
    10:3-5 Jesus asks a question regarding "what did Moses command" with regard to
    divorce. In Mar 12:26 he refers to the burning bush recorded in Exo 3, as being
    in the book of Moses. According to the DH, the account of the burning bush was
    not written down until at least the time of Solomon. In Luk 5:14 Jesus commanded
    the cleansed leper to go and make his offering "just as Moses commanded".
    According to critical scholars, the relevant section of the Law was not written
    until at least the time of Hezekiah. In Luk 24 there are two references to the
    Pentateuch as being the words of Moses, once by Luke in v 27 and once by Jesus
    in v 44. In Joh 7:19 we read of Jesus castigating the Jews for not obeying the
    law which Moses gave. 
    
    And in Joh 5 we come to a very important reference. In vv
    45-47 we read: "Do not think that I will accuse you to the Father: there is one
    that accuseth you, even Moses, in whom ye trust. For had ye believed Moses, ye
    would have believed me: for he wrote of me. But if ye believe not his writings,
    how shall ye believe my words?" (KJV) Clearly in none of these refs is there
    even the slightest hint that Jesus allowed for the possibility of most of the
    Pentateuch being written during or after the time of Hezekiah, or of it being
    put into the form that we now have sometime after the return from exile. For
    believers in Christ like ourselves, these claims by Jesus carry enough weight to
    carry the argument by themselves. For skeptics and for critical scholars, they
    are claims only but the fact remains that these are still clear claims. Jesus
    did not believe in anything even remotely like the DH. (DB)