Isaiah 52:10 (King James Bible) the LORD hath made bare his holy arm in the eyes of all the nations
The 1840 edition dropped the definite article the in the phrase “all the nations”. This loss appears to be a typo rather than due to editing. This reading was followed in the early RLDS textual tradition, but the original the (which is present in 𝓟 as well as in the corresponding Isaiah passage) was restored in the 1908 edition. Similarly, the 1837 edition omitted the definite article from the phrase “all the nations” in the following instance:
For discussion, see that passage.
In the original Book of Mormon text, there are 28 occurrences of “all nations” (including two occurrences in the witness statements) and 17 occurrences of “all the nations”, so either reading is theoretically possible. But when we consider the 33 cases where “all (the) nations” is not postmodified, we find that all 28 instances of “all nations” are without postmodification, while there are only five instances of “all the nations” without postmodification. And strikingly, all five of these cite Isaiah 52:10 (the first and last instances are paraphrases rather than exact quotations):
In other words, outside of biblical quotations, the Book of Mormon text consistently reads “all nations” rather than “all the nations” whenever there is no postmodification. This predominance is quite probably the reason why the 1840 edition accidentally omitted the the in Mosiah 12:24 (but, it turns out, in none of the other four quotations of Isaiah 52:10). The critical text will maintain all five of these cases of “all the nations”. (There is one additional case of this phraseology derived from Isaiah 52:10; in this sixth case, the definite article the is present in all the textual sources, including 𝓞, but the all is lacking, namely in 1 Nephi 22:10: “unless he shall make bare his arm in the eyes of the nations”).
Summary: Maintain in Mosiah 12:24 the use of the definite article the in the phrase “all the nations”, which is also the reading in the corresponding King James text for Isaiah 52:10.