@Davïd Altogether helpful. I initially thought it must be (and the Wikipedia article starts out by labeling it thus), but it's different from the other types of FoS given by Wikipedia (and re-iterated in our Substantially Informative Tag Wiki [SITW]) in that it's a syntactical rather than a lexical "figure". I see now that SITW also links to Robert Bradshaw indicating that it qualifies.

@Susan All I can say is that hendiadys is considered a figure of speech in all the theological and hermeneutical books I have read, but that's not to say some would consider otherwise.

@Susan @ScottS I actually misread Susan's original question, and my "Hmmm..." was a confused and hurried edit (before the tiny window of opportunity lapsed!). It still seems to me slightly different from many "FoS"s, in that it's much more likely to be a judgment call than the more typical ("lexical") "FoS"s. FWIW.

@Davïd More likely to be a judgment call than most syntactic phenomena we might compare it to too, and a bit of syntax that I can't get myself to "hear" (for nouns anyway -- the common verbal pairs don't really bother me), which is why I would like to figure out how we decide. I haven't able to find any "serious" discussion in the Hebrew resources, I guess because it's not really a Hebrew-specific thing, but it seems to show up there a lot.