Here the original text read either “that they could” (according to the printer’s manuscript) or “that they would” (according to the 1830 edition). Later in the LDS text, beginning with the 1907 vest-pocket edition, the third person they was changed to the second person ye and the conditional would was replaced by the future will. These two changes made the whole passage read as a direct quote rather than just the first part (“except ye repent of all your iniquities … ye will in no wise be delivered”). Finally, the 1911 LDS edition deleted the that before the ye will; this shorter reading has been followed in subsequent LDS editions. Once the entire passage is changed into a direct quote, the subordinate conjunction that needs to be removed since in modern English we expect that to introduce an indirect quote.
As explained under Helaman 14:4–5, it is possible for only part of a passage to be a direct quote. Thus here in 3 Nephi 3:15 the critical text will not remove the conflict between the initial except-clause (which is a direct quote) and the subsequent that-clause (which is an indirect quote). Moreover, it is possible here that the direct quote could be considered an emphatic conditional, a Hebrew-like construction that is found in a few other places in the original text. For discussion of the emphatic conditional, see under 1 Nephi 19:20–21 or, more generally, under hebraisms in volume 3.
The crucial textual issue here in 3 Nephi 3:15 is whether the original manuscript read “that they could in no wise be delivered” (the reading in 𝓟) or “that they would in no wise be delivered” (the 1830 reading). If 𝓞 read would, then Oliver Cowdery must have changed would to could when he copied from 𝓞 into 𝓟. On the other hand, if 𝓞 read could, then the 1830 typesetter must have changed could to would. When we examine the mix-ups in the history of the text between could and would, we find that there are only two instances:
Since Oliver caught his error in Helaman 9:41, there isn’t any example of him (or the 1830 typesetter, for that matter) ever permanently mixing up these two modals.
Ultimately, it appears that we will have to rely on internal evidence (usage elsewhere in the text) to determine for 3 Nephi 3:15 whether the original text read would or could. When we examine other passages that refer to people being delivered from something or someone, we find that there are no other examples of this type in the passive (as either “would be delivered” or “could be delivered”, the phraseology here in 3 Nephi 3:15). But there are a few cases in the active where either would or could will work. And in those cases where variation is possible, the evidence supports would over could when referring to the Lord delivering people from something or someone:
In contrast, there are three cases of “could deliver” where the Lord is negatively specified as the only one that can deliver the people, but it is always in contrast to everyone else being unable to do so:
From the Lord’s point of view, the issue in delivering people deals with whether he wants to deliver them; he is always able to do so. Thus the modal would is appropriate when referring to the Lord delivering people. With humans, however, the issue is whether they are able to deliver the people, not whether they want to, not only in the three examples listed above, but also in the following example that refers to Mormon’s inability to deliver his people:
The problem in 3 Nephi 3:15, however, is that the sentence is in the passive and the agent is left unexpressed. One can interpret “would be delivered” as implying that the Lord would deliver them. On the other hand, “could be delivered” can be interpreted as implying that anyone (humans as well as the Lord) could deliver them. Thus it is very difficult to decide here between would and could. Perhaps would should be favored because the preceding text refers to the Lord and implies that if the people will repent they will be delivered by the Lord (“as the Lord liveth / except ye repent of all your iniquities and cry unto the Lord …”). The critical text, on this slightest of differences, will therefore restore the 1830 reading with would since the context suggests that the Lord would be the one delivering the people.
Summary: Restore in 3 Nephi 3:15 the 1830 reading with the modal would and the indirect quote (with the subordinate conjunction that and the third person plural pronoun they): “that they would in no wise be delivered out of the hands of those Gaddianton robbers”; the evidence for the indirect quote is firm since that is also the reading in 𝓟; the preceding direct quote (“as the Lord liveth / except ye repent of all your iniquities and cry unto the Lord …”) suggests that if the people repent and cry unto the Lord, then they would be delivered, presumably by the Lord, thus making would (the 1830 reading) favored over could (the reading in 𝓟), given usage elsewhere in the text.