We do not have the original manuscript for these two verses, but the printer’s manuscript shows that for the first example Oliver Cowdery initially copied the text as councils (a typical misspelling of his for counsels); Oliver immediately caught his error in the number and erased the final s, giving the singular. The occurrence of the pronoun it in the next clause further supports the use of the singular (“for they set it aside”). If the original manuscript read as council (that is, counsel ), then one could interpret this correction in 𝓟 as showing a tendency on Oliver’s part to write the plural rather than the singular. In the next verse, Oliver writes councils once more (that is, counsels), but this time there is no correction in the number. The parallel use of the same basic expression—“they hearken (not) unto the counsel(s) of God”—could be used to argue that both cases of counsel(s) should be in the singular. The tendency for Oliver to incorrectly write the plural in the first case supports the possibility of error in the second case.
On the other hand, one could interpret the change in verse 28 of the plural councils to the singular council as a case of editing—namely, Oliver noticed the following it and before the ink was fully dry, he erased the s from off the end of councils. If so, one could argue that the text in verse 28 actually intended to have the plural councils (or counsels in standard orthography), even though the plural was contradicted by the following it. Under this interpretation, the plural councils in verse 29 (standing for counsels) would be perfectly acceptable. Obviously, no easy solution is apparent.
Elsewhere in the text there are references to God’s counsels (that is, in the plural):
But there is also one reference to God’s counsel (that is, in the singular):
Note in particular that both Helaman 12:5 and 2 Nephi 28:30 refer to giving or lending an ear to God’s counsel(s). It appears that either singular or plural is possible.
We should also note that the Doctrine and Covenants has three examples of the plural “counsels of God”, all in a single revelation that was given during the time Joseph Smith was translating the Book of Mormon:
This revelation dates from July 1828, after Joseph Smith had finished dictating the first 116 pages of the original manuscript. The language of the Lord’s early revelations to Joseph during the time of the Book of Mormon translation shows that the plural counsels is perfectly acceptable.
This competition between counsel and counsels is also found when the text refers to the counsel(s) of individuals. The following two passages in 2 Nephi 27–28 have the same basic phraseology except that one is in the singular and the other in the plural:
Once more, parallelism suggests the possibility of error, but it is difficult to tell whether the singular counsel in 2 Nephi 27:27 should be edited to counsels or the plural counsels in 2 Nephi 28:9 should be edited to counsel. We have the same problem in 2 Nephi 9:28–29. The easiest solution is to accept the earliest textual sources and allow variation between singular and plural. And usage elsewhere shows that we can have either counsel or counsels.
Summary: Following the variant usage throughout the text, we use the earliest textual sources to determine whether we have counsel or counsels; this results in singular/plural variation for counsel(s) in 2 Nephi 9:28–29 and similarly for 2 Nephi 27:27 and 2 Nephi 28:9.