It is generally accepted that the Doctrine of John reached its present form sometime in the aftermath of the Islamic conquest of Mesopotamia. There are many reasons to assume that parts of it, if not all of it, are much older, but here and there within the texts are references, some oblique and some not so oblique, to Muhammad and Islam. One such reference can be found on p. 45, lns. 1-2 of the Doctrine of John, which Lidzbarski translates as follows:
ṭubẖ lman ḏbhazin dara
bṣira ḏbišlum šlim
Wohl dem, der in diesem mangelhaften
Zeitalter des Bišlom heil geblieben ist.
Blessed is he who, in this defective
era of “Bišlom,” has remained whole.
From Lidzbarski’s perspective, bišlum is a pun (or ein Calembour, as he describes it); Bišlom is an oblique reference to Islam, consisting of the Persian prefix bi- “without” and the Arabic word salām “peace,” which has been Mandaicized to šlum for some reason. I’m not convinced; bi- may be the modern Persian (“Farsi”) form, but the contemporary Middle Persian form would have been abē-, not bi-. If the joke hinges upon a Farsi preposition, either this portion of the text was composed considerably after the early Islamic period (when most scholars accept that it acquired its present form), or its author would have had to wait a long, long time for his audience to get the joke—at least two or three centuries. Talk about bad timing!
Lidzbarski’s interpretation stuck, though, and Pallis (1926, 213) went even further, suggesting that bišlum is nothing more than the word Islām influenced by the word Muslim. This strikes me as clever, but perhaps a bit too clever. For a denizen of that selfsame “defective age” to recognize Islam qua Islam as opposed to, say, the worship of the planets, “Hagarism” (as it was generally known to Syriac-speaking Christians), or “Mohammedanism” (as it was known to Europeans throughout the greater part of the last fourteen centuries), it would have required a considerably more “modern” sensibility than that which is generally attributed to the polemical tracts of Late Antiquity. As a further objection, I know of no contemporary Aramaic dialect in which the word “Islam” or any calque of this word appears, raising the question of whether pre-modern non-Muslims ever employed this term, or whether they were even familiar with it. If not, what is the point of using it in a pun?
The interpretation of the term bišlum as “Islam” (which also appears in A Mandaic Dictionary) rests wholly and squarely upon this passage. Everywhere else within the corpus of Mandaic texts, including elsewhere within this manuscript, and indeed within this very same chapter, bišlum means “peacefully” or “at peace.” As it happens, a strong case can be made that it means that here, as well. It seems to me that the only wordplay within this verse depends upon the contrast between the terms bṣir “lacking” and šlim “whole:”
Happy is the one who, in this defective / lacking
age, is the one who has come to an end peacefully / intact.
The implication being that, in the “defective age” of the author, it was more common to end in pieces than end in peace.
Of course, reading Islam out of the picture has ramifications for the dating of this portion of the text. If we accept the traditional interpretation (that of Lidzbarski, Pallis, Drower, and Macuch), then we must accept that this portion of the text is post-Islamic. If we do not accept his interpretation, then there is no reason to assume that it is post-Islamic—of course, there’s also no immediately obvious reason to assume that it isn’t post-Islamic, but there was certainly no shortage of potential candidates for the role of mangelhafte Zeitalter throughout the period of Late Antiquity.