In the book Drudgery Divine, J. Z. Smith portrays Christianity and mystery religions in their late-antique phase as similar simultaneous parallel developments. He emphasizes diversity in all the religions, against the monolithic assumption that underlies the usual project of comparing "the" Jewish religion, "the" Christian religion, and "the" Pagan type of religion.Drudgery Divine is an expose of the biased and flawed nature of the Protestant, anti-Catholic project of portraying early Christianity as completely non-Catholic, non-ritualist, and non-initiatory. This Protestant scholarly project was based on illegitimate approaches to comparison of early, pre-Catholic Christianity to the pagan/Hellenistic religions.
The Protestant project sought to portray Christianity as far from ritual and initiation and mystery-religion as possible, and implicitly equated Catholic practices with Hellenistic ritual, initiation, and mystery, arguing that because pure, original Christianity was not at all like Hellenistic religion, original Christianity was not at all like Catholic Christianity.
According to the Protestant scholars, original Christianity was completely unlike Catholic Christianity, being strictly a matter of revealed, not secret religion; being strictly a matter of straightforward rational ethics, not initiation and ritual; being strictly a matter of sermon study-lectures, not magic-like ritual practices; being strictly a matter of doctrinal principles of pure faith, not ritual activity.
Insofar as the older Jewish religion could be portrayed as unlike Hellenistic secret ritual initiation, the Protestant scholars emphasized that real, original Christianity derived purely and strictly from the Jewish religion, as opposed to having anything to do with pagan/Hellenistic (read 'Catholic') secret ritual initiation.
According to those Protestant scholars, the word 'mysterion' in Jewish writings has only one meaning to consider, and this meaning is purely secular, and simply connotes 'secret', and does not connote secret ritual initiation -- therefore, the use of the word 'mysterion' in original (which is to say, non-Catholic) Christianity had nothing to do with Hellenistic-type (read 'Catholic-type') secret ritual initiation.
Smith's book does not serve the purpose of putting forth an elaborated correct positive model of the nature of earliest Christianities. Its focused purpose is to sweep away the bunk, biased, covert project driven by anti-Catholic concerns, to enable the next generation of scholars to completely re-approach the question of the relationship of early Christianity to Hellenistic religion, including an adequate treatment of multiplicity within Christianity and within the other religions, and development over time.
He points out that some kinds of Christianity were similar to some kinds of Hellenistic religion.
One of many tenets of the Protestant project of comparing original Christianity/Jewish religion against Hellenistic/Catholic religion, Smith briefly points out, is the idea that the Jewish religion was completely unlike secret ritual initiation.