There is no chapter break after verse 35 in the 1830 edition. The current break obscures the function of these two verses as a transition from the condemnation of the plurality of wives to the next theme, which will be the Nephite relationship with the Lamanites.
Verse 34 ends the condemnation. Jacob says: “for ye have done these things which ye ought not to have done.” They contradict current law as given to Lehi, and which should be binding upon them.
Verse 35 introduces the issue of the Lamanites. We remember at this point that Jacob has told us that his definition of Lamanite is any who are against them, or basically, any who are not Nephites. In most ancient societies, there was great animosity towards the outsider, and they were subject to almost codified prejudice. That is what we see here. The Lamanites are considered opposite of the Nephites, and, therefore, Jacob uses them as a juxtaposition to what the Nephites are doing.
When Jacob declares that “ye have done greater iniquities than the Lamanites,” it would have been almost inconceivable. By cultural definition the Nephites would assume themselves better. After all, it was the Lamanites who were cursed, with the assumption that therefore the Nephites were blessed.
This statement both highlights their sin and transitions into the next discussion.