Ammon (Son of Mosiah) references the teachings of Nephi

At the end of his 14 years as a missionary among the Lamanites, Ammon preaches to his brothers about the greatness of God, which we find in Alma 26.  In that chapter he says the following:

18 Behold, we went forth even in wrath, with mighty threatenings to destroy his church.
19 Oh then, why did he not consign us to an awful destruction, yea, why did he not let the sword of his justice fall upon us, and doom us to eternal despair?
20 Oh, my soul, almost as it were, fleeth at the thought. Behold, he did not exercise his justice upon us, but in his great mercy hath brought us over that everlasting gulf of death and misery, even to the salvation of our souls.

First of all, this is an internally consistent reference to Mosiah 27:10.

Perhaps even more interesting are references to the "sword of [God's] justice" and a "gulf of death and misery" from the teachings of Nephi (son of Lehi) found on the small plates.

Ammon was not a keeper of the records, but his father Mosiah-2 was. King Mosiah-2 was given the small plates of Nephi by King Benjamin (see Mosiah 1:16). King Benjamin had been given these records from the descendants of Jacob who kept them for several centuries (see Omni 1:25).

I like to imagine that as a young boy, Ammon listened to his grandfather read the stories of Nephi. These stories would have included Nephi teaching his brothers about the meaning of their father's vision of the tree of life.  In 1 Nephi 12, we read the following:

18 And the large and spacious building, which thy father saw, is vain imaginations and the pride of the children of men. And a great and a terrible gulf divideth them; yea, even the word of the justice of the Eternal God, and the Messiah who is the Lamb of God, of whom the Holy Ghost beareth record, from the beginning of the world until this time, and from this time henceforth and forever.

Note that in this verse, this "great and terrible gulf" is directly compared to the "word of the justice of the Eternal God." Royal Skousen has postulated that in this verse, word should be sword. The error occurred while Oliver Cowdery was copying the original manuscript to create the printer's manuscript. He misread Christian Whitmer's handwriting. Read more about that here.

All of this is very interesting to me for the following reasons:

1. According to the best evidence we have, Alma 26 was likely dictated at least one month before 1 Nephi 12. The naturalistic hypothesis would then require Joseph Smith to remember this reference to the the sword/gulf by Ammon. Over one month later he would dictate the source material Ammon references. Some weeks after that, he would dictate the events explaining how the records passed from person to person in a way that would allow Ammon to hear Nephi's words. Good memory, Joseph!
2. The gulf/sword/justice/judgment metaphor conjures an old Islamic idea of As-Sirat, which (from wikipedia), "is, according to Islam, the bridge which every human must pass on the Yawm ad-Din ("Day of the Way of Life" i.e. Day of Judgment) to enter Paradise. It is said that it is as thin as a hair and as sharp as the sharpest knife or sword (because of its danger) but in fact it is wide, and at one end it will be hung at the eastern wall of Haram al-Sharif (Jerusalem's Temple Mount)." (The sword/justice/judgment metaphor also alludes to "Cherubim and a flaming sword" from the garden of Eden account, which has its own temple relevance. See 1 Nephi 15:30.)
3. In some naturalistic models, Joseph Smith (and his alleged co-authors, possibly including Oliver Cowdery) are sometimes said to have done extensive research and writing of the text, which Joseph memorized (or secretly read to his scribe). This is how, without any supporting evidence, the naturalistic model attempts to account for internal consistency and references to real ancient religious metaphors. Then we are to believe that these same authors/co-conspirators didn't catch a transcription error (sword becoming word). In the divine origin model, this is easily explained--Oliver didn't know the significance of the "sword/gulf/justice" metaphor because he hadn't played any role in producing the text outside of acting as a scribe.
4. In other naturalistic models, Joseph simply riffed on Biblical themes and incorporated that into his 19th century understanding of native american culture. These models fail to account for the inclusion of these details in such an internally consistent way.
5. This type of evidence supporting the divine authenticity of the Book of Mormon seems to be completely overlooked by most critics. This is because, in my opinion, they either haven't studied the book in enough depth to notice these details, or they gloss over it because they don't have a good naturalistic explanation. They'd rather rely on a hoodwinking approach and assume the reader will buy what they are selling. This is a big reason why I believe their naturalistic hypotheses can be dismissed, until such time as they come up with an explanation for this type of evidence that explains the evidence we have in the text  and is backed up by actual evidence.
6. This is yet another example of evidence that the later contributors to the Book of Mormon studied the small plates of Nephi.