The typesetter for the 1841 British edition misread works as words. The subsequent LDS edition (1849) restored the correct works. For a list of mix-ups between word(s) and work(s), see under Alma 12:12–14. There are no instances in the original text of “the word(s) of justice”, but there are three more of “the work(s) of justice”:
The critical text will maintain “the works of justice” here in Alma 42:22. (For an example where the current text has an instance of “the word of justice”, an error for “the sword of justice”, see under 1 Nephi 12:18.)
Summary: Maintain in Alma 42:22 works, the reading in all the earliest textual sources (“the works of justice would be destroyed”).