Here we have a strange series of conjoined verb forms: “ye have … and have … and hath”. Obviously, “ye hath” is grammatically incorrect, which explains why Joseph Smith edited the hath to have. David Calabro (personal communication) suggests that the text here originally read it hath and that early in the transmission of the text the pronoun it was accidentally dropped, thus creating the odd “ye have ... and have ... and hath”. Note, in particular, that the preceding verbal conjunct has no explicit subject (“and have”) and yet it does have the correct verb form for ye—namely, have. One wonders, then, why the final verbal conjunct shouldn’t have also read “and have”.
Calabro points out that elsewhere the allegory refers only to the trees of the vineyard as bringing forth fruit (28 times). In one case, there is a reference to the Lord himself as bringing forth fruit: “that I may bring forth again the natural fruit” (verse 61); the vineyard, of course, is the Lord’s, so if the vineyard brings forth the natural fruit again, then metaphorically the Lord does as well. Early in the allegory, there is a reference to the servant bringing branches to the master to be burned (verse 7), but there are no references to the servant bringing fruit to the master of the vineyard. Two earlier references, however, refer to the trees in the vineyard as “bringing forth fruit unto the master of the vineyard”:
Thus in verse 75, if the predicate “hath brought unto me again the natural fruit” is referring to the vineyard itself as once more bringing forth natural fruit, then all is explained, including the resultive clause that immediately follows: “that my vineyard is no more corrupted”. Basically, we can interpret this passage as having a long, intervening parenthetical statement about how successful the Lord and his servants were in their labor:
The critical text will therefore emend Jacob 5:75 to read “and it hath brought unto me again the natural fruit”. It is quite possible that the pronoun it was accidentally omitted during the early transmission of the text, either as Oliver Cowdery took down Joseph Smith’s dictation or as Oliver copied from 𝓞 into 𝓟. See Jacob 5:24 for another example in the olive tree allegory where the pronoun it was apparently dropped in the early transmission of the text.
Summary: Emend Jacob 5:75 by adding it before the original verb form hath: “and it hath brought unto me again the natural fruit”; this single emendation clears up several difficulties in the earliest extant reading.