Greg Wright suggests (personal communication, 4 March 2009) that the word you is missing here, that the original text read “neither do I tell you these things that thereby I might accuse you”. Nearby, there are two instances of the same expression but with the you (later in this same verse and in verse 17):
More generally, the verb tell typically takes an indirect object (such as you) or an equivalent prepositional phrase with the preposition unto. In all, there are 102 such cases. But there are also 8 cases (including the one here in Mosiah 2:15) where there is no indirect object or equivalent prepositional phrase, including one that is similar to the case here in Mosiah 2:15:
The critical text will therefore maintain the current reading here in Mosiah 2:15—without any you —since it is possible.
Summary: Maintain in Mosiah 2:15 the lack of the indirect object you after the verb tell in the clause “neither do I tell these things that thereby I might accuse you”; 3 Nephi 26:1 provides some support for the ellipted you in expressions like this.
The first part of the last paragraph in this write-up should be slightly revised to read as follows:
In two other places, Oliver Cowdery may have intended to write are but ended up accidentally crossing the e to write art, just as in Mosiah 2:24. In these two instances, the art was transmitted into the 1830 edition (and subsequently removed from the text in the editing for the 1837 edition):
The remainder of the paragraph, with its two citations, follows as originally written.
The dashes in the third line in the Mosiah 2:34 citation should be revised so that only the except- clause is set off parenthetically; thus the whole citation should read as follows:
I say unto you that there are not [one >js any 1|one A|any BCDEFGHIJKLMNOPQRST] among you
—except it be your little children—
that have not been taught concerning these things but what knoweth that ye are eternally indebted to your heavenly Father
The except- clause could be set off by dashes or commas. Also note that in the critical text the word heavenly in the phrase “your heavenly Father” (at the end of the citation) is not capitalized.
Actually, a better interpretation for the expression “I would call your attention” (here in Mosiah 3:1 and also in Mosiah 4:4) derives from the archaic meaning ‘to ask, invite’ for the verb call (mentioned under definition 4a in the Oxford English Dictionary). Thus “I would call your attention” could be interpreted as meaning ‘I would invite your attention’. Or as Alison Coutts points out (personal communication), one could paraphrase the expression as “I would call for your attention”.
Remove the hyphen from less-prescriptive, giving “There is less prescriptive motivation for deleting the that ”.
After listing all the cases of “observe to keep the commandments” in the text, I wrote that only here in Mosiah 4:30 was the phrase to keep omitted, but I should clarify that this is the only example of the omission persisting in the text. In one case, there is some indirect evidence that to keep was initially omitted in 𝓞; in Helaman 15:5 there is insufficient room for to keep in the lacuna between surviving fragments of 𝓞, so it was probably supralinearly inserted. See the discussion under Helaman 15:5 in part 5 as well as lines 33–34 of the transcript for page 399ªof 𝓞 (on page 506 in volume 1 of the critical text).
The dashes in the Mosiah 2:34 citation should be placed so that they set off only the except- clause:
The same change is referred to in the addendum listed above under Mosiah 2:34.
The adjective effectual is also used in the King James Bible, as in this well-known example from the New Testament: “the effectual fervent prayer of a righteous man availeth much” (James 5:16).