In Mosiah 13:33 we find the following words of Abinadi:
For behold, did not Moses prophesy unto them concerning the coming of the Messiah, and that God should redeem his people? Yea, and even all the prophets who have prophesied ever since the world began--have they not spoken more or less concerning these things?
According to Brant Gardner, it is not clear to which part of the scriptures Abinadi is referring when he proclaims Moses as prophesying the redemption of Israel through the Messiah. The modern Book of Moses is certainly clear on this point, but those are sections of the Book of Moses that do not correspond to our received text of Genesis. Perhaps there were some differences in the brass plates and these included more specific prophecies from Moses which we do not have now.
It is fascinating that it is Moses that is mentioned, and not Isaiah. Abinadi is going to cite Isaiah, but he first references Moses. The rhetorical reason for so doing is obvious. He has spent time showing the gospel of the Messiah as superior to the law of Moses. He clinches the argument by declaring that Moses himself knew this, and prophesied of this Messiah that the priests deny.
While this is a tremendous rhetorical ploy, it is a poor one for a clever writer who is writing the Book of Mormon as a novel or a fantasy. Here would be an easy place to submit a proof text that is accepted (such as the Isaiah citations that will come). However, rather than the safe entry, we have this odd one that would appear to be deniable from the current Bible. A good imposter would have avoided this argument, even though it is powerful. [Brant Gardner, "Book of Mormon Commentary," [http://www.highfiber.com/~nahualli/] LDStopics/ Mosiah/Mosiah13.htm, pp. 16-17]