One wonders here if the relative pronoun which is missing from this passage. We expect something like “lest he should look for that which he had not ought”. (Here I ignore the difficulty of the archaic “had not ought”, which Joseph Smith later edited to “ought not”; for discussion of this change, see under ought in volume 3 as well as under 1 Nephi 15:3.)
Elsewhere in the original text, there were 175 occurrences of that which. One of these was removed by Joseph Smith in his editing for the 1837 edition (see the discussion regarding “than that which we have been” in Mormon 9:31), so the current text has 174 occurrences of that which. Of these instances, 12 occur as the object for the preposition for; except for here in Mosiah 8:13, there are no instances of the preposition for taking a that-initial relative clause as its object. There is one instance of for that which where the printer’s manuscript initially lacked the which:
The original scribe here in 𝓟 was the unknown scribe 2. Later, Oliver Cowdery proofed this part of 𝓟 against 𝓞 and restored the which, but he inserted it in the wrong place (after the word moth rather than before it). Clearly, the text does not intend to say that Christ will be sold “for that moth which doth corrupt” (the corrected reading in 𝓟). Rather, Christ will be sold “for that which moth doth corrupt” (the 1830 reading). This passage in 3 Nephi is based in part on the language of the Sermon on the Mount (quoted in 3 Nephi 13:19):
The important point about the text in 3 Nephi 27:32 is that the original scribe in 𝓟 accidentally omitted the relative pronoun which. Such an error supports the possibility that in Mosiah 8:13 the scribe of 𝓟 (here Oliver Cowdery) could have accidentally omitted the which after that.
On the other hand, in support of the reading in Mosiah 8:13 without the which, David Calabro points out (personal communication) that the King James Bible has a number of examples where that occurs instead of the expected that which:
There are, of course, examples of the expected that which in the King James Bible, such as the following parallel to Matthew 13:12 and Luke 19:26 (both cited above):
Calabro also observes that in the following Book of Mormon passage the that could be interpreted as equivalent to that which rather than the subordinate conjunction that:
In other words, Nephi wants his readers to remember what he has spoken, not that he has spoken. Thus there is evidence from the King James Bible as well as from 2 Nephi 31:4 to support the invariant that in Mosiah 8:13 (“lest he should look for that he had not ought”). The critical text will leave the current reading in Mosiah 8:13 unchanged, despite its difficulty for modern readers. Paul Huntzinger (personal communication, 12 April 2004) wonders if there isn’t some additional error with respect to the use of the phrase “had not ought” (“ought not” in the current text). Normally, we would expect an infinitive clause after “had not ought” (or “ought not”). In this instance, the verb is ellipted, yet it is recoverable from the preceding text (“lest he should look for that which he had not ought”). The infinitival marker to is also lacking in the ellipsis; a more expected reading here would be “lest he should look for that which he had not ought to”. Virtually every other example in the text of ought is followed by an infinitive clause headed by to, but there is one exception:
This second passage provides another example of ellipsis where the verb is recoverable from the preceding text (“they did not look unto the Lord as they had ought”). And once more, there is no to following the clause-final ought, which shows that the original reading in Mosiah 8:13 without a to following “had not ought” is perfectly acceptable whenever the infinitive clause is ellipted.
Summary: Retain the reading in Mosiah 8:13 that lacks the relative pronoun after that (“lest he should look for that he had not ought”); such usage can be found in the King James Bible as well as in 2 Nephi 31:4 (under one interpretation of the text); in addition, there is no need to add an infinitival to after the modal verb ought in Mosiah 8:13 (or in 1 Nephi 15:3).