The 1837 edition deleted both for ’s in this passage, the first one by mistake. The second of these deletions was marked by Joseph Smith in the printer’s manuscript and was motivated by the desire to remove the nonstandard use of for to from the text (see the discussion under Mosiah 13:25 and, more generally, under for to in volume 3). Here in Alma 16:16, the 1837 typesetter apparently let his eye stray down from the first for to the second one—that is, to the for in for to that would have been crossed out in his copytext, a copy of the 1830 edition:
Thus the 1837 typesetter ended up accidentally omitting the preceding for as well. There was clearly no motivation for deleting the first for. The following clause is used to explain why there was no inequality among the people: namely, the Lord’s Spirit was upon “all the face of the land”. Obviously, there is nothing syntactically inappropriate about the first for. The same precise usage can be found elsewhere in the text, as in the following cases of “for the Lord did ”:
Summary: Restore the conjunction for near the beginning of Alma 16:16: “for the Lord did pour out his Spirit on all the face of the land”; also restore the original use of for to in “for to prepare the minds of the children of men”.