Here the original reading in the printer’s manuscript has two instances of the same difficult reading—namely, the past-tense form commanded rather than the expected present-tense command. What is especially difficult here is that neither of these occurrences of the past-tense commanded were corrected by Oliver Cowdery when he proofed 𝓟 against 𝓞. This suggests that 𝓞 itself read commanded both times. So the question here is whether the past-tense usage can be justified in any way. The past-tense definitely does not seem to work, especially given that throughout this part of the chapter, from verse 26 through verse 32, king Mosiah otherwise uses only the present tense in discussing his proposed change in government. Thus the repeated past-tense commanded seems quite incongruous. But at the same time, one is hard-pressed to explain the origin of the error, if it is one.
The 1830 typesetter, John Gilbert, rejected the past-tense ending for both cases of commanded and with a pencil crossed out the -ed ending both times in 𝓟. Joseph Smith, in his editing for the 1837 edition, also crossed out the -ed ending for the first instance, using his typical heavier black ink (thus overwriting there the 1830 typesetter’s original crossout in pencil). All the printed editions have continued with the two present-tense occurrences of command.
One argument worth considering here is that the scribe in 𝓞 for this part of Mosiah 29 may not have been Oliver Cowdery but some other scribe who was not particularly adept. See, for instance, the discussion under verse 21, which argues that this unknown scribe tended to misspell ye as yea and also seems to have misspelled dethrone as deathrone. One could by extension assume that this scribe of 𝓞 accidentally added the plural -ed endings to the verb command. In fact, one might wonder if the repetition of “and I commanded you to do these things” in this verse involves some kind of dittography. Of course, Hyrum Smith, the scribe here in 𝓟 (and also not particularly adept as a scribe), might be responsible for these difficulties in tense and repetition.
One further possibility is that Joseph Smith himself, when he dictated the text here, accidentally added the -ed twice. I have noticed that in reading off “and I command you to do these things”, I naturally tend to add the -ed since it creates a fully rhythmic alternating sequence of unstressed and stressed syllables:
a˘nd I co˘mma nde˘d yo u to˘ do the˘se thı ngs
Thus there might have been a natural tendency to accidentally supply the -ed ending here. It is even possible, of course, that the scribe in 𝓞 added the rhythmically satisfying -ed ending as he tried to take down Joseph’s dictation. Thus prosody could explain the origin of the two difficult past-tense forms here.
David Calabro (personal communication) has suggested the possibility that the first occurrence of commanded could be correct but the second was originally command; yet because of the nearly identical phraseology of “and I command(ed) you to do these things”, the following instance of command was accidentally changed to commanded. Another possibility is that one or both of these instances of commanded may have originally read in the perfect, as have commanded, so that there was a loss of one or two have’s in the early transmission of the text. Thus there seems to be a plethora of ways to emend the two instances of commanded.
Yet there may be a way to justify the use of the past-tense commanded. Here in verse 30 king Mosiah may not be referring to the present moment, but to some future time when the people may need to judge their own judges, as described in the immediately preceding verses:
Verse 30 then refers to the fact that the people should keep in mind that king Mosiah commanded them to do these things in the fear of the Lord—that is, the first these things in Mosiah 29:30 refers to how the people should judge their own judges. But king Mosiah also wants them to keep in mind that he commanded them to set up this system of judges and to not have a king. Thus we get a seemingly unnecessary repetition of “and I commanded you to do these things”:
In fact, the second that-clause (“that if these people commit sins and iniquities / they shall be answered upon their heads”) seems to be referring back to what king Mosiah previously stated in verse 27 regarding the future:
In others words, verse 30 applies to possible future events described in verses 27–29, not to the present moment. Thus the use of both instances of the past-tense commanded can be justified from the perspective of the future.
Given this interpretation, we can accept the two past-tense uses of commanded in Mosiah 29:30. In fact, a well-designed paragraphing system for the text could place all of verses 27–30 in its own separate paragraph, thus helping the reader to realize that verse 30 is a comment on the immediately preceding verses 27–29.
Summary: Restore in Mosiah 29:30 the original two occurrences of the past-tense form commanded; in verse 30 king Mosiah is referring to the future (explicitly referred to in verses 27–29), and he wants the people in those future days to remember that he commanded them to maintain the rule of judges and to follow its system of safeguards.