Tracing literary relationships across traditions turns up overlaps constantly. A phrase from Sirach appears in a saying attributed to Jesus, an image from 1 Enoch surfaces in the letter of Jude, a legal principle worked out in the Dead Sea Scrolls anticipates a ruling in the Mishnah, and a Greek philosophical category organizes an Alexandrian Jewish reading of Genesis. Describing those relationships is the point of comparative reading. The difficulty comes at the next step, when overlap begins to feel like sameness and the traditions that produced the overlapping texts blur into a single tradition that each community drew on as it needed.
Israelite writers, Jewish writers in Alexandria who worked in Greek and for a Greek-speaking world, the authors of the New Testament, and the rabbis whose discussions were collected in the Mishnah and the Talmuds were pursuing different projects, answering to different communities, and working under different rules about what a text is permitted to mean. A connection between two of their texts is a genuine fact about literary history, and it says almost nothing on its own about whether the two traditions agree. Treating the connection as agreement is the most common way comparative reading goes wrong, since it converts a description of how texts relate into an argument about which tradition got the text right.
Comparison Depends on Difference
Comparative study has failed in two opposite directions, and both failures come from the same mistake about what comparison is for. One approach sets out to demonstrate that a text or a tradition is unique, treating every resemblance to another text as a threat to be explained away. The other sets out to demonstrate that two things are at bottom the same, treating the differences as incidental. Neither is really comparison, because comparison depends on a mixture of sameness and difference, which makes every comparison an analogy rather than an equation.[1]
A comparison is therefore unfinished until the differences have been described with the same care as the similarities. The well-known charge that comparative work on the New Testament overstates similarity and then treats it as proof that one text produced the other was aimed at a related habit, the habit of working from published lists of parallels rather than from the sources themselves. Such a list gives the reader two excerpts already stripped of the arguments they were serving, and without those arguments there is no way to see what each text was doing with its material.
Each Tradition Reads by Its Own Rules
Rabbinic interpretation runs on stated rules. Thirteen of them, attributed to Rabbi Ishmael, govern how legal conclusions may be drawn, among them the argument from the smaller case to the larger one and the linking of two passages on the strength of a single word they share, while a further principle holds that no verse ever loses its plain sense however much interpretation is built on top of it. The tradition also distinguishes between reading for the sense a passage carries in its setting and reading for implications the text does not state directly, and it does not treat the first as automatically more truthful than the second.
Judging that practice against the standards of a different tradition produces a verdict rather than a description. The rabbis did not share the modern devotion to the simple literal meaning, and their habits placed no obligation on them to prefer it, so a reading that looks like abandoning the text by one standard was not abandoning it by theirs, and it broke no rule they recognized.[2]
A verse shared by several traditions can therefore mean something different in each without any of them breaking its own rules. Habakkuk 2:4 in Hebrew describes a person of integrity who lives by his own faithfulness, the Greek Septuagint attaches the faithfulness to God instead, and Romans quotes the Greek version in the service of a claim about trust in Jesus.
Alexandrian Jewish Texts Are Not Waystations
Jewish writing from Alexandria attracts a particular version of the blurring problem, since it stands chronologically between the Hebrew Bible and the New Testament and is read as the link between them. Aristobulus, who wrote there in the middle of the second century BCE, has been handled as an early and undeveloped Philo, his readings measured against the fuller system of symbolic interpretation Philo assembled more than a century later. The correction is to read Aristobulus without reference to Philo and to judge each writer on his own terms, at which point Philo is neither the completion of something Aristobulus began nor a figure who arrived without predecessors. Both drew on Alexandrian traditions of reading, each drew differently, and the difference shows different aims at different stages rather than one continuous approach toward a single destination.[3]
The same habit governs how the Greek Septuagint is often handled, as a stage on the way to the New Testament rather than the scripture of Greek-speaking Jewish communities who read it as their own. Its distinctive translation choices become interesting only where a New Testament author later quoted them, and its other decisions, made generations earlier for reasons of its own, go unexamined.
Distinct Traditions Without a Clean Break
Keeping traditions distinct is not the same as claiming they separated early and cleanly. The familiar model of a single decisive split between Judaism and Christianity in the first or second century has one real virtue, which is that it lets both be approached as traditions in their own right with equally strong claims on the shared heritage of the Hebrew Bible and the Jewish literature of the centuries before the Temple was destroyed in 70 CE. Its defect is that it settles by definition a question the evidence leaves open, since the boundaries of Jewish and Christian identity stayed fluid for centuries afterward and neither was ever a single thing to begin with.[4]
One long-running habit made the problem worse in both directions at once. Christian accounts of a degenerate Judaism awaiting correction were answered by claims about a single official Judaism of the centuries before Jesus that led inevitably to the Mishnah and the Talmuds, and both descriptions treated one tradition as the true continuation of Israel's scriptures and the other as a departure from them. Neither description holds up against the sources. The publication of the Dead Sea Scrolls exposed how varied Judaism was in the period, since specialists in early Jewish writing, early Christianity, and rabbinic texts all found sources bearing on their own questions in one collection, and the continuities run toward rabbinic Judaism and toward early Christianity at the same time.
Variety on that scale rules out treating any later tradition as the natural continuation of what came before, because there was no single thing available for it to continue. It equally rules out the opposite move of assigning each later tradition a sealed ancestry of its own, since the material they drew on overlapped heavily and they went on borrowing from one another long after the boundary between them was supposed to have hardened.
Every Tradition Advances on What Came Before
Building on an earlier tradition and thereby replacing it is not a peculiarly Christian move, and identifying the pattern in one tradition does not set that tradition apart from its neighbors. Rabbinic Judaism displaces priestly Judaism at the opening of Pirkei Avot, a tractate of the Mishnah, where the chain of transmission runs from Sinai to Joshua, from Joshua to the elders, from the elders to the prophets, and from the prophets to the men of the great assembly, leaving the priests out of the line of custody altogether. Traditions generally claim to have improved on an earlier or rival tradition, and most hold that if they are right the rival must be wrong or at least incomplete.[5]
Recognizing that pattern is what makes it possible to describe rather than to repeat it. Treating an earlier text as valuable is a different act from treating as valid the ongoing tradition of people who hold the same text sacred and read it otherwise, and the two get conflated whenever a shared text is used to argue that one tradition's reading was already present in the other's scripture. The argument may be worth making inside a tradition, where it does the work of self-definition and explains to insiders why their own reading matters. It is not a finding about literary history, and presenting it as one puts a comparative argument in the service of a conclusion the comparison never established.
What Description Requires
A connection described well settles three things, the direction in which the material moved, the rules under which each side was reading, and what each side did with the material that the other did not. The first is a historical question and usually the hardest, the second requires knowing both traditions well enough to recognize when a move that looks arbitrary is in fact regular, and the third is what actually distinguishes the two and is also the part most often skipped, since a list of resemblances reads like a result while a list of divergences reads like an admission that the connection was weak.
Divergence is not a weakness in the connection but the substance of it. A community that receives a text and reads it under rules of its own has done something specific, and what it has done becomes visible only against the readings it declined to give. Erasing the difference in order to make the traditions agree removes the only evidence that a relationship was being negotiated at all, and it leaves each tradition holding a text it is no longer allowed to read in its own way.