Nephi and Malachi's Common Source

2 Nephi 26:4 is strikingly similar to Malachi 4:1.  Nephi spoke of what will happen to the wicked Nephites at the time of the coming of the Savior among them, while Malachi spoke of what will be of the wicked at the Second Coming, but the outcome is the same: the proud and the wicked will burn as stubble.  Clearly Nephi couldn't have been quoting Malachi because Nephi lived before Malachi and so his words were not a part of the plates of brass.  But it seems likely that both could be paraphrasing a third source which came before both of them.

 This would have to have been something that was in their record that we don't have today, like the words of Zenos.  There are more similarities between the language of Nephi and Malachi that bear this out.  In 2 Nephi 25:13 Nephi spoke of the Savior who would “rise from the dead, with healing in his wings,” just as Malachi 4:2 spoke of the “Sun of righteousness” who would also “arise with healing in his wings.”  The phrase “Son of Righteousness” is used by Nephi in 2 Nephi 26:9 and is a phrase which is used rarely in scripture.  Malachi appears to be the only Old Testament prophet who employed it.  In 1 Nephi 22:24 Nephi wrote that “the time cometh speedily that the righteous must be led up as calves of the stall,” using the same phrase as Malachi 4:2.  All of this evidence seems point to some unknown earlier prophet whose words were used by both Nephi and Malachi.  And the way that Nephi integrated bits and pieces throughout his writings shows the depth to which he had studied and pondered the plates of brass that he had.  Before the Savior quoted the words of Malachi to the Nephites, we read that he had "expounded all the scriptures in one" and I think that is what we see in the writings of Nephi (3 Nephi 23:14).  He seemlessly integrated words from the prophets in the plates of brass as if they were his own, enabling him also to expound the scriptures into one unified whole and unchanging message of the gospel.