The question of the sources behind the Gospel of John relates closely to the question of authorship. Since we concluded that he was an eyewitness to the events described, being John the son of Zebedee, the author is an important source for his own gospel. But what needs to be investigated is whether, in spite of his being an eyewitness of the events that he is describing, John used sources in writing his gospel. It is not impossible that an eyewitness would use sources other than his own memory or private memoranda.
 

1. John and the Synoptic Gospels

One should not expect complete agreement between a text and a source or sources upon which it is dependent. But how many differences can be tolerated before one suspects that two texts are not literarily related at all? Apart from the Passion and Resurrection narratives, where one would expect significant agreement, John differs from the synoptic gospels in content, with some exceptions. But even in the parallels in the Passion and Resurrection narratives and in the few parallels outside of them, John and the synoptics diverge greatly in the details of their respective accounts. The question whether there is enough similarity to warrant the conclusion that John is literarily dependent on one or more the synoptic gospels has long been debated (for a catalogue of positions until 1974, see Teeple, The Literary Origin of the Gospel of John, chap. 6). (Few hold that the synoptics were literarily dependent on John.) There are two sorts of parallels between John and the synoptics to consider: Narrative and sayings material.
 

1.2. Possible Narrative Parallels Between John and the Synoptic Gospels

1.2.1. List of Possible Narrative Parallels

A. John 1:32/Mark 1:10 = Matt 3:16 = Luke 3:22 The Spirit as a dove coming upon Jesus

B. John 2:13-22/Mark 11:15-19 = Matt 21:12-17 = Luke 19:45-48 Clearing of Temple

C. John 4:46-54/Matthew 8:5-10, 13 = Luke 7:1b-10 Healing of the Official's Son/Centurion's Servant

D. John 6:1-15/Mark 6:32-44 = Matt 14:13-21 = Luke 9:10b-17 Feeding of five thousand

E. John 6:16-21/Mark 6:45-52 = Matt 14:22-33 Walking on water

F. John 12:1-8/Mark 14:3-9 = Matt 26:6-13 / Luke 7:36-50 Anointing (at Bethany)

G. John 12:12-19/Mark 11:1-10 = Matt 21:1-9 = Luke 19:28-40 Royal Entry into Jerusalem

H. John 13:21-30/Mark 14:18-21 = Matt 26:21-25/Luke 22:21-22 Identification of betrayer

I. John 13:36-38/Mark 14:27-31 = Matt 26:31-35/Luke 22:31-34 Prediction of Peter's denial

It should also be noted that there is one case of a sharing a common order of pericopes in John and the synoptics; in each Jesus' walking on water follows his Feeding of five thousand.

1.2.2. Example of Possible Narrative Parallel (See also Feeding of the Five Thousand in "The Synoptic Question")

B. John 12:12-19; Mark 11:1-10; Matt 21:1-9; Luke 19:28-40 Royal Entry into Jerusalem
 

B. John 13:36-38/Mark 14:27-31 = Matt 26:31-35/Luke 22:31-34 Prediction of Peter's denial
 

1.2.3. In two of the cases of possible narrative parallels between John and the synoptics, it is doubtful whether the same event in Jesus' life is being depicted (Clearing of Temple; Healing of the Official's Son/Centurion's Servant). In cases of genuine parallels, there is insufficient agreement to justify postulating literary dependence: John's account of an event narrated in the synoptic has too few parallels and insufficient verbatim agreement to support the claim that he used one or more of the synoptics as sources. In addition, John and the synoptic differ in their accounts on important details, the presence or absence of which is difficult to explain on the hypothesis of literary dependency. The one instance of agreement of order of pericopes is insignificant, since the two traditions can be explained as belonging together in the tradition because this was the actual order of events.
 

1.3. Possible Sayings Parallels Between John and the Synoptics

1.3.1. Possible sayings parallels between John and the synoptics are as follows:

A. John 4:35 / Matt 9:37-38 = Luke 10:2 Harvest metaphor

B. John 4:44 / Mark 6:4 = Matt 13:57 / Luke 4:24 Prophet without honor

C. John 5:29 / Matt 25:46 Final judgment

D. John 10:1-15 / Luke 15:3-7 / Matt 18:12-14 Shepherd and sheep

E. John 10:14-15 / Matt 11:25-27 Hidden knowledge revealed

F. John 12:25 / Mark 8:35 = Matt 16:25 = Luke 9:24 Life lost and gained

G. John 12:39-40 / Mark 4:12 = Matt 13:13 = Luke 8:10 Quotation of Isa 6:9-10

H. John 12:44-45 / Mark 9:37 = Matt 18:5 = Luke 9:48 / Matt 10:40 Receiving Jesus

I. John 13:16 / Matt 10:24 (see Luke 6:40) Servant not greater than master

1.3.2. Examples of Possible Sayings Parallels:

A. John 4:35; Matt 9:37-38; Luke 10:2
 

B. John 12:25; Mark 8:35; Matt 16:25; Luke 9:24
 

1.3.3. Some of these possible sayings parallels are so dissimilar, that one cannot really equate the Johannine saying with its alleged parallel in one or more of the synoptics; they clearly are not two versions of the same saying (John 4:35/Matt 9:37-38 = Luke 10:2 Harvest metaphor; John 10:1-15/Luke 15:3-7/Matt 18:12-14 Shepherd and sheep; John 10:14-15/Matt 11:25-27 Hidden knowledge revealed; John 12:44-45/Mark 9:37 = Matt 18:5 = Luke 9:48/Matt 10:40 Receiving Jesus ). Similarly, although they both cite Isa 6:9-10, John and the synoptics do so different contexts (John 12:39-40/Mark 4:12 = Matt 13:13 = Luke 8:10). The remaining possible sayings parallels arguably are the same sayings, but have insufficient verbatim agreement to support the hypothesis of literary dependence.
 

1.4. Evaluation of the Evidence

Since there is such little agreement between John and the synoptics, prima facie, it does not appear that John is literarily dependent on the synoptics. The only way that one could maintain that there is literary dependency would be to posit considerable redactional freedom on the part of the author of the Gospel of John. C. K. Barrett, for example, concedes that John did not make use of Mark in the way that Matthew did; rather he was much less tied to the Markan text for his outline and the contents of his gospel (The Gospel According to John, 42-54). Nevertheless, according to Barrett, the few instances of "verbal coincidence" between some of the parallels between John and Mark can only be accounted for by postulating an intermittent literary dependence or, at least, that the author of the fourth gospel had read Mark and "often--perhaps involuntarily--echoed Mark's phrases when writing about the same events" (45). (Barrett provides a list of the more striking "verbal coincidences" [44-45].) Barrett also believes that it is plausible that John knew and used Luke.

    Earlier, B. F. Streeter argued that the author of the Gospel of John was not an eyewitness (contrary to all the evidence) but was a "Christocentric mystic," conscious of his own prophetic inspiration, who freely blended his own mystical insights with material from Mark and Luke (The Four Gospels: A Study in Origins, 363-463). The parallels between John and Mark noted above prove John's dependence on Mark. Streeter's conclusion that John used Luke rests principally on the fact that only in Luke are Mary and Martha mentioned (Luke 10:38) and the name Lazarus occurs (Luke 16:19-20).  (This is a different Lazarus than the one in John). There are also a few minor parallels between John and Luke, according to Streeter, which justify his conclusion: John 20:3-5/Luke 24:12 Peter's visit to the tomb; John 20:36/Luke 24:36 Jesus' use of "Peace be with you" as a greeting; John 20:26-27/Luke 24:40 Jesus shows hands to Thomas (John) and Jesus shows his hands and feet (Luke). (For a another argument for John's dependence on Luke, see J.Bailey, The Traditions Common to the Gospels of Luke and John; F. Grant argues that John used Mark and Q traditions rather than Luke ["Was the Author of John Dependent on the Gospel of Luke?" JBL 55 [1936] 285-307.)

    It is obvious that any attempt to prove that John is literarily dependent on one or more of the synoptic gospels is tenuous to the point of being unbelievable. Such arguments tend to be circular. It is probably better to assume that there is no literary dependency. P. Gardner-Smith argued in 1938 that in all cases of alleged literary dependency on the synoptics, it is more feasible to hold that John derives his material from oral tradition (St. John and the Synoptic Gospels). This accounts for the occasional parallel between them and the far more numerous discrepancies. Gardner-Smith's aim was to consider "whether it is easier to account for the similarities between St. John and Synoptists without a theory of literary dependence, or to explain the discrepancies if such a theory has been accepted" (x). This position was re-asserted by C. H. Dodd in 1963 (Historical Tradition in the Fourth Gospel). Now neither Gardner-Smith nor Dodd believed that John the son of Zebedee wrote the fourth gospel. But if this is granted then it becomes even less probable that John is literarily dependent on the synoptic, since its author would be an eyewitness. Arguably, John the apostle was aware of the existence of one or more of the synoptic gospels and these may have affected what he chose to include in his own gospel, but he did not use any the synoptic gospels as sources for his own (see Clement of Alexandria's explanation on the origin of John's gospel).
 

1.5. Conclusion

How much John is dependent on his own memory or perhaps private notes and how much he relied upon more publicly accessible tradition is impossible to know. It seems, however, that the lack of similarity between John and the synoptics argues for a certain amount of independence from the more publicly accessible tradition. Thus, if he wrote in light of the synoptics, John's aim seems to be to supplement the synoptic portrayal of Jesus from private reminiscences and perhaps notes. In addition, it should be noted that John was heavily influenced in his own theological discourse by his distinctive portrayal of Jesus in his gospel: In his letters, John sounds very much like the Johannine Jesus.
 

2. Other Alleged Sources of the Gospel of John

Eliminating the synoptic gospels as sources for John does not preclude the possibility that its author used other, written non-canonical sources. There has been much work done on Johannine source criticism in the past few centuries. D. F. Strauss in the mid-19th century introduced the metaphor of "a seamless robe" (suggested by John 19:23), to describe the position--to which he took exception--that there were no detectable literary seams in the text indicating that different sources were used in its composition. Since that time, scholars have debated whether John is a seamless robe or more quilt-like (to introduce another metaphor) in character, a miscellany of diverse sources.

    Numerous "partition theories" have been proposed to account for the suspected sources used in John; these attempt to separate out material from the gospel and assign it to its respective source. In his commentary on the Gospel of John, which appeared in 1941, Rudolf Bultmann claimed to be able to detect the existence of four distinct sources, the work of the writer, and the work of a later redactor. The four sources that formed the material out of which the writer composed his gospel were:

1. Prologue, which was of gnostic origin, since it depicts the descent of the heavenly redeemer; the author was an ex-gnostic.

2. Signs Source (Semeia-Quelle) made up of narrative reporting Jesus' miracles: This alleged "signs-source" is reconstructed from Bultmann’s commentary by D. M. Smith to have consisted of: 1:35-49; 2:1-12; 4:4-9, 16-19, 25-30, 40, 46, 47, 50-54; 6:1-3, 5, 7-13, 16-22, 25; 7:2-10; 5:2-15; 7:19-23; 9:1-3, 6-121, 24-28, 34-38; 10:40-42; 11:2, 3, 5-7, 11-19, 33, 34, 38-44; 12:37, 38; 20:30, 31. This source supposedly portrayed Jesus as a theios-aner, a miracle worker whose signs were intended to inspire faith in him. (The author of the Fourth Gospel tempers this thaumaturgic portrayal of Jesus by introducing criticisms of those who demand signs in order to believe [see John 4:48].)   Bultmann interprets the fact that in John two of Jesus’ "signs" are called his first and second (2:11; 4:54) to indicate that the author was drawing upon a signs source that presumably enumerated Jesus’ signs. There are, however, no further examples of enumerated signs in the Gospel of John.  According to Bultmann, the statement in 20:30 that Jesus did more "signs" than are recorded is the conclusion of the "Signs Source."

3. Revelation Discourse Source (Offenbarungsreden-Quelle) made up of isolated sayings of Jesus: According to Bultmann, the "Revelation Discourse Source" was a gnostic document in which are contained the sayings of a gnostic redeemer figure who brings salvation by bringing revelatory knowledge; this accounts for the assumed gnostic flavor of the teaching of the Johannine Jesus. This hypothetical source is reconstructed by D. M. Smith to have consisted of:  1:1-5, 9-12, 14, 16; 3:6, 8, 11-13, 18, 20, 21, 31-36; 7:37, 38; 4:13, 14, 23, 24; 6:27, 35, 48, 47, 44, 45, 37; 5:17, 19-21, 24-26; 11:25, 26; 5:30-32, 37, 39, 40; 7:16-18; 5:41-44; 8:14, 16, 19; 7:6, 7, 28, 29, 33, 34; 8:50, 54, 55, 43, 42, 44, 47, 45; 10:11, 12, 1-4, 8, 10, 14, 27-30, 9; 12:27-29, 31, 32; 8:31, 32, 34, 35, 38; 17:1, 4-6, 9-14, 16, 17, 20-23; 13:31, 32; 15:1-2, 4-6, 9, 10, 14, 18-20, 22, 24, 26; 16:8, 12-14, 16, 20-24, 28; 14:1-4, 6, 7, 9, 10, 12, 14, 16-19, 26, 27; 18:37.  A feature of these sayings is the use of rhythmic forms, such as antithetical parallelism.

4. Passion Narrative: Bultmann holds that the author of the Gospel of John had access to a narrative relating Jesus' death and resurrection that was distinct from but related to the synoptic passion narratives.

    These four major sources were taken up by the author (who was not John the apostle), and blended together to become the Gospel of John. The author weaved together the signs and discourse sources with the help of links supplied the author himself; to the signs/discourse portion of the gospel was added a Passion Narrative and the Prologue. In Bultmann's view, somewhat later an editor interpolated material into the Gospel of John, and there were some transpositions of material (D. Moody Smith presents a careful summary and analysis of Bultmann's source theory (The Composition and Order of the Fourth Gospel [New Haven: Yale U. Press, 1965].)

    Bultmann's criteria for distinguishing these sources from one another were: 1. style (Stilkritik);  2. Ideological differences between sections;  3. Obvious interpolations and artificial connections between different types of material.

    Bultmann's claim that the different types of material in the gospel differ from one another in style and therefore indicate that they originate from different sources has been scrutinized, with the result that his views turn out to be unacceptable. Rather, based on stylistic criteria, one must conclude that the Gospel of John is a literary unity. In reaction to Bultmann’s work on the Gospel of John, E. Ruckstuhl demonstrated that there was a literary consistency in the gospel (Die literarische Einheit des Johannesevangelium, 1951); he did this by identifying a set of fifty distinctly Johannine literary characteristics and demonstrating that these could be found scattered more or less evenly throughout the gospel. This is the opposite of what one would expect if John had used sources, since each source would have its own distinctive style. (E. Schweizer anticipated Ruckstuhl's work in his Ego Eimi: Die religionsgeschichtliche Bedeutung der johanneischen Bildreden, zugleich ein Beitrag zur Quellenfrage des vierten Evangeliums, 1939.)  As P. Parker cheekily puts it, "It looks as though, if the author of the fourth Gospel used documentary sources, he wrote them all himself" ("Two Editions of John," JBL 65 (1956) 304).

    Most have accepted Ruckstuhl's conclusion, but in recent years there have been criticisms of Ruckstuhl's method and attempts to demonstrate anew the existence of different sources in John's gospel. In particular, many attempt to salvage Bultmann’s hypothesis of a "Signs Source" underlying the Gospel of John. These attempts include: Robert Fortna, The Gospel of Signs: A Reconstruction of the Narrative Source Underlying the Fourth Gospel; W. Nicol, The Semeia in the Fourth Gospel--Tradition and Redaction; Howard Teeple, The Literary Origin of the Gospel of John. These arguments are not incredibly convincing, and do not even agree with one another in their results (which is a sign that something is wrong). The attempts to discern the alleged sources used in John tend to be circular: variations in vocabulary and syntactical features are assumed to be evidence of different sources. What is assumed wrongly is that such variations are not compatible with single authorship (see J. A. T. Robinson, The Priority of John, 10-23).

    In conclusion, since he was an eyewitness and did not need sources, and there are no obvious indicators that he used sources, it follows that John probably wrote his gospel without written sources, unless he wrote them himself. If he did use written sources, these are unrecoverable. To quote, B. F. Streeter, who wrote before the appearance of Bultmann’s commentaty on John, "For if the sources have undergone anything like the amount of amplification, excision, rearrangement and adaptation which the theory postulates, the critic’s pretense that he can unravel the process is grotesque. As well to hope to start with a string of sausages and reconstruct the pig" (The Four Gospels: A Study of Origins, 377).