Here the original verb form ends in the third person singular ending -eth. One could theoretically argue that this archaic inflectional ending shows that the subject noun phrase, “the Father and the Son and the Holy Ghost”, is a singular. In other words, one could use the inflectional ending to support the claim that the subject in this relative clause represents a trinitarian unity of the Godhead. Such an argument, however, is not supported by usage elsewhere in the original text of the Book of Mormon. There we find numerous examples of verbs where the archaic third person singular ending -(e)th occurs with plural subjects, as in the 1 Nephi preface: “Nephi’s brethren rebelleth against him” (original text). In that case, rebelleth was grammatically emended to the standard third person plural form rebel in the 1920 LDS edition, just as in that same edition the form beareth here in Ether 5:4 was grammatically emended to bear. Moreover, as explained under Mormon 7:7, there doesn’t appear to have been any theological motivation in the history of the Book of Mormon text for editing the grammatical number of the verb for the phrase “the Father and the Son and the Holy Ghost”. In general, the critical text will restore the earliest instances of the third person singular ending -(e)th, even when the subject is plural.
Summary: Restore the third person singular form beareth in Ether 5:4 even though the subject is the plural “the Father and the Son and the Holy Ghost”.