As noted in the discussion under Mosiah 4:18, this is the only passage in the text that does not use doeth and doth according to standard biblical style; namely, we expect doth whenever do acts as an auxiliary verb, but doeth whenever do is the main verb. This is also the only example where the auxiliary verb do is separated by some distance from its main verb (namely, bring), with the result that in the original text here both do and bring take on the forms of finite main verbs. Thus the earliest text reads “and even so doeth every man that is cursed bringeth upon himself his own condemnation”. The 1830 typesetter decided to emend these two verbs to the expected forms, doth and bring, as if the sentence read more simply as “and even so doth every man … bring upon himself his own condemnation”. Such an emendation agrees, for instance, with Mosiah 14:1, for which we get the correct do form: “yea even doth not Isaiah say : who hath believed our report”).
David Calabro has suggested (personal communication) that the verb form bringeth might be an error for bringing; in other words, the original text here read “and even so doeth every man that is cursed / bringing upon himself his own condemnation”. Another possibility is that there was originally a subject he pronoun before bringeth; that is, the original text read “and even so doeth every man that is cursed : he bringeth upon himself his own condemnation”. Yet both these conjectural emendations seem rather strained, although not impossible. They do have the virtue that they each propose a single error as the source for the difficult reading in 𝓟. But the actual meaning of the passage seems to be reﬂected in the 1830 emendation.
Historically, the doth form is an unstressed form of the verb do, which is what we would normally expect for the auxiliary verb form of do. On the other hand, doeth is the stressed form of the verb, which is what we expect when do is the main verb. Here in Alma 3:19 the relative isolation of the do verb makes one tend to expect the stressed form doeth even though this do verb is an auxiliary verb. Interestingly, the relative isolation of doth led the 1874 RLDS edition to accidentally revert to the original doeth (yet the 1830 bring was left unchanged). The 1908 RLDS edition restored the grammatically correct 1830 reading “doth ... bring”.
The critical text will restore the two original finite verb forms, doeth and bringeth, since their use in 𝓟 could be intended. Clearly, the complex subject “every man that is cursed” has something to do with the repeated occurrence of the -eth inﬂectional ending in this passage. There may be some primitive error here in Alma 3:19, but thus far no fully satisfactory emendation has been proposed.
Summary: Restore the intended, but grammatically incorrect, use of “doeth ... bringeth” in Alma 3:19; the complex noun phrase “every man that is cursed” (which ends in a postmodifying relative clause) seems to have led to this unique use of two finite verb forms.