3 Nephi 6:12: And the people began to be distinguished by ranks, according to their riches and their chances for learning; yea, some were ignorant because of their poverty, and others did receive great learning because of their riches.
4 Nephi 1:26: And they began to be divided into classes; and they began to build up churches unto themselves to get gain, and began to deny the true church of Christ.
While this is clearly documented for Meso-America, which is where Allen J. Christenson looks for the evidence, this is not at all what is happening in the descriptions of the Old Testament or the KJV. As a result, the terms "rank" and "class" that the BoM uses to discuss these events do not occur in the KJV in this form (non-military) in the case of "rank" and not at all with respect to the term "class". The OT assumes that trade is in the hand of the elites, be they patriarchs or kings such as Salomon, or the merchant princes of Tyre. For the BoM that is a problem and a source of social criticism.
Alma 32:2: And it came to pass that after much labor among them, they began to have success among the poor class of people; for behold, they were cast out of the synagogues because of the coarseness of their apparel.
An interesting aside in this context is the use of the word "lawyer". In the KJV, "lawyers" is the translation of the Greek term "οἱ νομικοὶ" (e.g. Luke 7:30, 11:45f, etc; Mathews 22:35; Titus 3:13); modern translations (including the LDS Bible dictionary) translate the word as "scribes".
In the BoM, the lawyers are men whose tasks conform to the modern notion of lawyer, i.e. legal advisors and prosecutors, attached to the judicial proceedings of a [debtors] court, where they (as well as the judges) are recompensed in the binary system of gold, silver and barley equivalences, for their time and effort (Alma 10:29-Alma 11:20). The BoM accuses the lawyers of being in it not for the justice, but for the recompense.
Alma 11:20: Now, it was for the sole purpose to get gain, because they [i.e. the lawyers] received their wages according to their employ, therefore, they did stir up the people to riotings, and all manner of disturbances and wickedness, that they might have more employ, that they might get money according to the suits which were brought before them; therefore they did stir up the people against Alma and Amulek.I find this as peculiarly modern a notion as I find the discussion about formation of elites.