Malachi 4:4 (King James Bible) remember ye the law of Moses my servant which I commanded unto him in Horeb for all Israel with the statutes and judgments
In his editing for the 1837 edition, Joseph Smith initially interpreted the which in this passage as referring to Moses, and thus he edited the which to whom in 𝓟. However, this interpretation was apparently rejected by the time the typesetting for that edition took place since the 1837 edition maintains the original which (as do all subsequent editions). The critical text will, of course, maintain the original which here even if it referred to Moses. For another example where which was edited to whom, in this case incorrectly, see the nearby discussion under 3 Nephi 21:11.
Summary: Maintain the original which in 3 Nephi 25:4, the reading of the earliest textual sources as well as the corresponding King James passage (in Malachi 4:4).