Not sure that either M-W or you, sjm, are on very stablke grounds, using the quasi-Jacobean English of the RSV as your benchmark for English Grammar.
I take your point, Verlangen (welcome, btw - glad to see you here) - it is not good modern grammar at all. The only real way out is to put "wages" into the singular. One does talk of one's "wage", if not so often as ones "wages", whereas to say that they "are death" contradicts the undoubted singularity of that event (well - I hope so, anyway!! - unless you are someone who "dies a thousand deaths" when something embarrasses you.)
But I suppose that the real point (and the saving of both sjm and M-W) is that it is an epigram that is definitely hallowed - both from its source (Saint Paul, no less) and from long usage. One accepts, therefore, the apparent grammatical inconsistency on the grounds of custom and practice.
