In Early Modern English, the past-tense form for the verb swear was typically sware, but this has been replaced in modern English by swore (in part under the influence of the past participial form sworn). For instance, in the King James Bible there are only examples of sware (83 of them, including swarest), none of swore. In the Book of Mormon, there are six passages where we have to consider whether the original text read sware or swore:
In all these instances (where extant), the scribe in the manuscripts is Oliver Cowdery. In two passages, he miswrote sware as swear:
𝓞 𝓟
Ether 1:33
Ether 8:14
swear swear swear
For these two cases, the original text seems to have read sware. In a third case, Oliver actually wrote sware in the original manuscript, but he changed it to swore when he copied from 𝓞 into 𝓟:
𝓞 𝓟
Alma 25:1
sware swore
This change suggests that in two cases where 𝓟 reads swore and 𝓞 is not extant that 𝓞 might have read sware:
𝓞 𝓟
Enos 1:14
Mosiah 19:4
swore swore
In preparing the transcripts for the original manuscript (see volume 1 of the critical text), I assumed as much and proposed that 𝓞 read sware for Enos 1:14 (see line 20 on page 114 of 𝓞). But the sixth example provides indirect evidence that sometimes Oliver Cowdery wrote swore in 𝓞:
𝓞𝓟
Ether 15:28 wore >+ swore
Here Oliver initially misread the verb in 𝓞 when he copied from 𝓞 into 𝓟 and wrote wore. A little later, with somewhat heavier ink flow, he corrected wore to swore. Most likely, 𝓞 read swore, which would explain why Oliver misread it as wore: he simply missed the initial s. If 𝓞 had read sware, it would have been less likely for him to have misread it as wore; such a misreading would require that he not only missed the initial s but also misread the a as an o.
This mixed evidence argues that in each case the reading should be determined by the earliest textual sources, with the understanding that swear is a misspelling for sware (obviously not swore). This decision gives us the following readings in the earliest text for the six cases of sware /swore:
In other words, the earliest text is evenly divided between sware and swore.
This variation for the past-tense form of swear is similar to that of the verb bear. The original text prefers the archaic bare, and Oliver Cowdery tended to spell bare as bear (given their identical pronunciation, /ber/). And like the case of sware/swore, the transmitted text has occasionally introduced the modern form, bore, in place of the archaic form, bare. One difference is that the earliest textual readings support a consistent use of bare in the original text in distinction to the competing use of both sware and swore. For a list of the original instances of bare, see under 1 Nephi 11:7. For a general discussion regarding both swear /sware and bear /bare, see swear and bare in volume 3. For a general discussion regarding sware /swore and bare /bore, see under past tense in volume 3.
Summary: Restore the archaic past-tense form sware in Alma 25:1 and Ether 1:33; also accept sware in Ether 8:14; in the other three cases where the original text could have read sware (Enos 1:14, Mosiah 19:4, and Ether 15:28), the earliest textual sources actually support swore.