
Joseph W. answered 04/20/19
Modern Hebrew for English Speakers
Great question! It's a tough one too... The word "panim" like you mentioned, is one that doesn't have a singular form unless you are using it to mean "facet." So you could look at it like the English word "moose". There is no plural form for this English word, so whether you are speaking of one moose or several, the word doesn't change. The Hebrew word "panim" works the same way except that it is always plural. FYI the Hebrew word for "water"(mayim) is the same way.
However, with the Hebrew word for God, it seems to be a plural word, but it doesn't function that way grammatically when used to mean "God". (this word can also be used to mean judges/rulers in Biblical Hebrew) This is unlike the above words that we mentioned that always function as plural.
So I can't directly answer your question; "Why is Elohim plural?" it seems to be plural, but doesn't function as a plural word. It would probably be a very interesting question to ask a rabbi about. And if you asked 2 rabbis you'd be sure to get at least 3 different answers. I'm not in any way a rabbi, but personaly I see this sort of "hidden/implied plurality" but still "singularity" as something that speaks to the oneness of God (a very Hebrew/Jewish thought), but also His ability to reveal himself in more than just one way.