The phrase "from the least to the greatest" shows that all the people of Israel are included in the phrase "all of them," regardless of how important they are. AT: "all of them, including the least powerful, the most powerful, and every one else, are greedy" (See: [[rc://en/ta/man/translate/figs-merism]])
This refers to the most powerful and most important people. AT: "the greatest people" or "the most powerful people" (See: [[rc://en/ta/man/translate/figs-nominaladj]])
The abstract noun "gain" can be expressed with the phrases "get more money" or "get more things." AT: "want to get more money by lying to people" or "strongly desire to get more things and will even trick people in order to get them" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])