There are two interesting variants in this verse. First of all, the verb form in the initial clause is comes rather than either cometh or come. Since the subject is plural (“all these gifts”), Joseph Smith emended the verb form comes to come in his editing for the 1837 edition—and in agreement with the come in the following clause (“and they come unto every man severally”). Although the third person singular ending -(e)s for plural subjects is comparatively uncommon in the earliest Book of Mormon text, there are nonetheless some examples, such as these:
Each of these was emended to the appropriate plural verb form in the 1837 edition. The critical text will restore these original instances of the -(e)s ending. And since such usage is possible in the original Book of Mormon text, the instance of comes will be restored here in Moroni 10:17, despite its ungrammaticality in modern English.
The second variant of interest here in Moroni 10:17 is the form severly in the printer’s manuscript. This appears to be a scribal slip for severally, which is how the 1830 typesetter interpreted it. The subsequent text has maintained severally. This interpretation of severly as severally is supported by the textual similarity between this passage and the King James language in one of Paul’s epistles:
Yet there is a possibility, rather slim though, that severly is actually correct. According to the Oxford English Dictionary, severly is an obsolete Scottish form of severally. Unfortunately, there are no other instances of the word severally in the Book of Mormon, so we cannot determine how the scribes might have dealt with other instances of this word. My suspicion, however, is that severally is correct here, especially since there are no actual citations for severly with the meaning ‘severally’ either in the online version of the OED or on Literature Online . Interestingly, these two online sources have quite a few examples where severely is spelled, intentionally it would seem, as severly. Of course, here in Moroni 10:17 severly is not the word severely. The critical text will therefore accept the 1830 interpretation of severly as severally, which is supported by the parallel language in 1 Corinthians 12:11.
Summary: Restore in Moroni 10:17 the original third person singular verb form comes (“and all these gifts comes by the Spirit of Christ”); such usage sometimes occurred in the original Book of Mormon text; also accept the 1830 typesetter’s interpretation of severly, the reading in 𝓟, as a scribal slip for severally; this reading is supported by the parallel language in 1 Corinthians 12:11.