Ross Geddes (personal communication, 28 November 2004) suggests that the subject pronoun it was accidentally dropped here in Ether 13:12 (thus “and when these things come / it bringeth to pass the scripture which saith …”). Indeed, for most instances in the active voice of “bring to pass”, a subject is normally specified (ten times), but not in the following case:
Note, however, that the following clause does have a subject it (“yea it has brought to pass an awful scene of bloodshed”). Perhaps the difference is that in the first instance there is an introductory adverbial of time (“from the first year to the fifteenth”), just like in Ether 13:12 (“when these things come”). The critical text will therefore maintain the earliest reading here in Ether 13:12 without any explicit subject for the verb phrase “bringeth to pass the scripture”.
Summary: Maintain the earliest reading in Ether 13:12 without any explicit subject for “bringeth to pass the scripture”; another example of this construction occurs in Alma 28:10.