A study of Bezae’s text in John 4:1–42 is attractive for a number of reasons. Not only is John 4 the best-preserved chapter in Origen’s monumental Commentary on John, but it is also the first entire chapter of John in which both Codices Sinaiticus (א) and Bezae (D) preserve a so-called “Western” text.
In fact, the textual character of Sinaiticus in John 1-8 is one the fascinating puzzles of textual research in the gospels. Short of actual historical contact with a tradition very much like that of Bezae, it is difficult to explain the remarkable parallels shared by this normally-solid Alexandrian witness with perhaps the most famously divergent of gospel manuscripts.
In his seminal article on the text of Sinaiticus in John, G. Fee focused on John 4 as the most “Western” of the early chapters of John, a situation that has proved convenient for my own study of Bezae’s layering in John 4:1-42.  (For details on this study and its method, see this previous post.) In fact, nine of Fee’s thirteen singular agreements between א and D and four of his seven sparsely-attested agreements are included in my data set. (For Fee’s data from John 4:1-42, see this page.)
As seen in the plot below, with points (o, Δ, +, ×, ◊, ∇) representing D’s readings by layer, Fee’s observations corroborate well with Bezae’s layering in John 4:1-42, where as we might expect, readings attested by א, color-coded in violet, exhibit a significant level of correspondence with D’s two Old Latin layers in the two small ellipses at the lower left:
Certainly, א’s correspondence with D’s Old Latin layers stands out against the remaining Greek witnesses, none of which has any significant representation in the Latin layers, while א is represented at half of the eighteen readings apportioned among the two Old Latin layers.
What is perhaps more striking though, is that the four sparsely-attested א-D agreements singled out by Fee (circled in yellow) do not fit cleanly inside any of the other six layers identified in the study, occupying an outlier position at the fringes of the layer boundaries (in fact, on the perimeters of the blue ellipses in layers 1 and 3). Remarkably then, even after we consider the Alexandrian, mainstream, and two Old Latin layers, א still attests an additional residual layer in common with D.
So from these remarkable parallels, can we say anything more about potential contexts for Bezae or its traditions? For a suggestion, we might turn to Bezae’s correctors:
As it turns out in his study of Bezae’s correctors, D. C. Parker notes a “striking” 62.5% (25/40) agreement between Bezae’s Corrector B and Sinaiticus together with its C-group of correctors, specifically the C[a] and C[b2] correctors, whom A. C. Myshrall places in the fifth to sixth centuries, apparently not long after Bezae’s production in ca 400.  Noting the possibility that Sinaiticus was in Caesarea at some point in the fifth or sixth centuries, Parker observes:
“there is evidence [from Corrector B] to suggest that Codex Bezae may also have been in Caesarea, or somewhere susceptible to Caesarean influence, at an early stage in its life, perhaps during the fifth century.” 
Parker then suggests that Corrector B had access to both a D*/d-like text and a א[c]-like text, whether combined or as individual manuscripts.  Of course, this plausible coincidence of location is just the kind of evidence we need to begin building a historical framework capable of accommodating the multiple shared layers we find in these two unlikely codices in John 1-8.
Yet there remain many questions. For example:
- Why were only the first eight chapters of John copied in this so-called “Western” text form?
- Was this a feature of the exemplar?
- Did the scribe start out correcting from a second “Western” exemplar and lose interest in chapter 8?
- Did the scribe choose an unauthorized “Western” MS and proceed until discovered and apprehended?
- Was the pericope adulterae in this “Western” exemplar at John 8?
- Was a MS chosen specifically because it attested the pericope adulterae without considering its divergent character throughout?
- Might dissension among producers of the MS over the pericope adulterae explain why the “Western” text form cuts off in chapter 8?
However we address these questions, the situation we find in א seems to reflect a real grappling with a text form much like that of D. This is surprising given what is often considered of D’s isolation in the Greek tradition. It may suggest though that whenever א was produced, whether in Caesarea or elsewhere, D’s tradition held a real attraction among at least some of the participants. We can only ask what brought this to an abrupt halt, as it were, almost in the act of copying.
 G. D. Fee, “Codex Sinaiticus in the Gospel of John: A Contribution to Methodology in Establishing Textual Relationships,” New Testament Studies 15 (1968) 23–44 at 32.
 D. C. Parker, Codex Bezae: An early Christian manuscript and its text (Cambridge: Cambridge University Press, 1992) 146; A. C. Myshrall, “Codex Sinaiticus, its Correctors, and the Caesarean Text of the Gospels” (Ph.D. Diss., The University of Birmingham, 2005) 102.
 Parker, Bezae, 144-148. But see also on the setting, D. Jongkind, Scribal Habits of Codex Sinaiticus (Piscataway, N.J.: Gorgias, 2007) 252-254.
 Parker, Bezae, 149.