The 1840 edition introduced the reading “a pure and a delightsome people” instead of “a white and a delightsome people”, the reading in the printer’s manuscript and the two earliest editions (1830 and 1837). The original manuscript is no longer extant here. The 1840 change of white to pure seems to be a conscious one and was probably made by Joseph Smith as a part of his editing for the 1840 edition. The change does not appear to be an accidental error based on any visual or phonetic resemblance between the two words. We do know that Joseph Smith made a few changes in the 1840 edition based on the original manuscript, but it is very doubtful that the original manuscript ever read pure here since such a reading would presume that Oliver Cowdery had miscopied the word as white when he produced the printer’s manuscript, a mistake that seems highly unlikely given the distinctiveness of the two words. No mix-ups of white and pure are found anywhere else in the whole history of the text, in either the manuscripts or the printed editions.
The early RLDS textual tradition followed the 1840 reading, pure, but in the 1908 edition the earlier white was restored since it was the reading of the printer’s manuscript. On the other hand, the LDS text followed the earlier reading until the 1981 edition, when pure (the 1840 reading) was adopted.
The text here in 2 Nephi 30:6 appears to be a reference to the curse that came upon the Lamanites as well as upon those who would intermarry with them:
Just before verse 6 in 2 Nephi 30, Nephi refers to “the remnant of our seed” and discusses how the Book of Mormon will be brought to them:
The question here is whether the phrase “the remnant of our seed” refers to only the descendants of the Nephites or more generally to all the descendants of Lehi and his people (namely, the Lamanites and the Nephites). Yet even under the more narrow interpretation (that is, Nephi is referring to only his own people), this remnant of the Nephites would have been forced to join with the Lamanites and ultimately to become indistinguishable from them:
In other words, the surviving descendants of the Nephites would have been forced to become Lamanites and over time indistinguishable from them; thus the reference in 2 Nephi 30:3–6 to “the remnant of our seed” becoming “a white and a delightsome people” will work irrespective of whether the possessive pronoun our refers to all the descendants of Lehi’s people (both the Lamanites and the remnant of the Nephites) or to the Nephites specifically. Therefore, the original use of white in 2 Nephi 30:6 is wholly appropriate.
Of course, the 1840 change of white to pure avoids all of this complex reasoning, especially the need to interpret the remnant of the Nephites as being dark skinned. In other words, the editing change to pure may represent a conscious attempt at avoiding what was perceived as a difficult reading (the Nephites are supposed to be light skinned), which therefore explains why the change from white to pure was made here—and only here—in 2 Nephi 30:6. There has never been any attempt to emend any of the passages that directly comment on the dark skin of the Lamanites:
In addition, Alma 3:7–19 refers to this dark skin as a curse and a mark set upon the Lamanites to keep them separate from the Nephites.
When the Book of Mormon text specifically refers to light-colored skin, it consistently uses the word white rather than pure. Moreover, the word white collocates with the adjective fair for most of these passages:
On the other hand, when white collocates with pure, we find that the passages describe a state of righteous perfection (referring either to the righteous at the day of judgment, to the garments of the righteous at that day, or to the fruit of the tree of life). In most of these passages pure and white collocate with the word spotless; all of these adjectives emphasize purity and cleanliness:
The critical text will therefore restore the word white in 2 Nephi 30:6; it is the earliest extant reading, and its occurrence there is consistent with usage elsewhere in the text.
We should also note here that the 1849 LDS edition accidentally lost the repeated indefinite article a in this conjoined construction (thus creating “a white and delightsome people”). The repeated a was restored in the 1981 LDS edition since the earliest text as well as the 1840 edition had the repeated a (even if white had been replaced by pure in the 1840 edition). For further discussion of such repetition of the indefinite article, see conjunctive repetition in volume 3.
Summary: Maintain in 2 Nephi 30:6 the original reading “a white and a delightsome people”, the earliest extant reading in the text; for the 1840 edition, white was replaced by pure, probably because of a perceived difficulty in allowing a change in skin color to apply to the descendants of the Nephites.