Here Oliver Cowdery wrote “one with another”; then considerably later the preposition with was changed to of (see line 29 on page 119 of 𝓟). The supralinearly inserted of was written with heavier and darker ink flow. The of does not look like Oliver Cowdery’s normal of, especially the formation of the descender for the f, but the o itself as well as the crossout and the insert mark looks like Oliver’s. Unlike most of his supralinear corrections, the ink strokes for the of are wobbly. Clearly, the correction was not immediate.
A similar correction is found a few lines later; there the word be was supralinearly inserted with somewhat heavier and darker ink flow:
Once more, the strokes of the inserted word are wobbly. And two pages later, in Mosiah 2:32, we have another supralinearly inserted of (in line 12 on page 121 of 𝓟) that is very much like the of here in verse 13 except there is no wobbling (the ink flow is still heavier but now not as dark). For this latter of, the o again looks like Oliver’s, but once more the descender for the f is different than normal (see the discussion under Mosiah 2:32).
All three of these distinctive changes could be due to later proofing of 𝓟 against 𝓞. Theoretically, the changes could be due to editing. And Oliver Cowdery may be the scribe, but we cannot be sure. I have already discussed a number of cases in this part of 𝓟 where Oliver Cowdery seems to have proofed 𝓟 somewhat later. In particular, we have the following supralinear corrections in 𝓟, all in heavier and darker ink flow and, in these cases, clearly in Oliver’s hand:
Omni 1:6 should not be verrified line 25, page 113
Omni 1:6 that line 25, page 113
Omni 1:17 many line 21, page 114
Omni 1:17 & line 23, page 114
Omni 1:23 to see his death line 36, page 114
Some of these corrections in 𝓟 appear to be due to proofing rather than editing. But that does not mean that some of these cannot be due to editing. See the discussion under the book of Omni for each of these supralinear insertions.
Elsewhere in the Book of Mormon, the phrase “one with another” is used only in reciprocal situations (that is, in situations where the relationship between the individuals goes in both directions). There are 29 occurrences of the phrase, as in the expression “to contend one with another”. On the other hand, the relationship in “one of another” can be considered nonreciprocal in Mosiah 2:13: one person is the slave while the other is the master. From this perspective, of is the easier reading here in Mosiah 2:13. But except for this one case of “one of another”, there are no examples of that phrase in the Book of Mormon. It is possible that Oliver Cowdery originally wrote “one with another” in 𝓟 simply because of its considerably higher frequency. Since “one with another” seems to be a scribal error here in Mosiah 2:13, the critical text will accept the later correction in 𝓟 as the original reading.
One other possibility is that the original text may have read “nor that ye should make slaves of one another” (that is, the of precedes one rather than follows it). If we accept this reading as the original, then we would have to conclude that Oliver Cowdery was correct to change with to of but wrong when he inserted the of in the same place where the with had been. It turns out, however, that there are no examples of the phrase “of one another” in the entire Book of Mormon text. Given the lack of evidence for this alternative word order (“of one another”), we should continue to rely on the corrected reading in 𝓟. Moreover, one another has a reciprocal meaning; as already noted, slavery is not a reciprocal relationship.
Summary: Retain in Mosiah 2:13 the corrected reading in 𝓟 (“nor that ye should make slaves one of another”), thus maintaining the semantic distinction between “one with another” and “one of another”.