Printed from http://tektonics.org/oral2.php
In an essay on oral tradition we demonstrated that within an ancient Jewish context, there was every reason to suppose that for whatever period the Gospel messages were transmitted orally, the transmission process was accurate and reliable. We noted that there was an 80% correspondence in the words of Jesus, and that under the paradigm of oral tradition, incidentals were allowed to be variable as long as the primary point was not affected.
In this brief essay we will discuss how this affects the Gospels and the differences between them.
We should stress that variations in oral tradition in no way contradicts the idea of inerrancy. The idea of inspiration as wooden and mechanical in all cases is something that the Scriptures never demand. Nor is there any indication that such variations were considered "erroneous" by the ancients, under whose paradigms we are compelled to work here. Skeptics must show that such variations were considered problematic by ancient commentators, not merely impose their own 21st-century literary values upon the text.
Albert Lord, in his essay entitled "The Gospels as Oral Traditional Literature" which appears in The Relationships Among the Gospels: An Interdisciplinary Dialogue, remarks generally upon oral traditional narratives as having "textual fluidity", such that they are "constantly being repeated without concern for word-for-word retelling of a set, established text."  Shorter forms such as proverbs or sayings are more likely to remain fixed than longer narrative. Of course, this agrees with what we have noted above about Jesus' own words being preserved the best; though Lord adds that shorter parts of a longer narrative "may attain a fair degree of fixity in the retellings of a given storyteller, or of narrators in a closed group, without conscious memorization." (Note that in the case of the Gospels, we would argue for conscious memorization.)
Lord's essay is primarily concerned with orality as it related to the question of literary dependence among the Gospels. Nevertheless, it provides relevant clues in terms of showing the potential effect of oral tradition on differences in the Gospels. Why might Matthew read "but when the sun rose" (heliou de anateilantos) while Mark prefers "and when the sun rose" (kai hote aneteilen ho helios)?
Critics preferring literary theories must construct scenarios explaining why Matthew, copying Mark, was motivated to make such a change. Lord's essay suggests that sometimes a simpler thesis fits the bill: oral tradition and its effects. He offers a parallel in a Serbocroatian song titled "The Captivity of Djulic Ibrahim". Here are the lines as they appear in the two versions:
Lord cautions (writing in 1976) that more study is needed before we have full comprehension of the transmission process; yet this example shows how oral transmission can create minor variations in verbiage. Lord notes as well that these variations come from two versions by the same singer; different singers can show greater divergence, as in this example from "Marko Kraljevic and Musa the Highwayman":
It is easy to see some parallels here to variations in verbiage in the Gospels. Lord notes in conclusion that the Gospels have certain characteristics of oral traditional literature, including the elaboration and expansion of parallel stories.
In this we are not pointing to any particular difference in the Gospels as the result of oral transmission. Differences, as we have noted, may also be due to a variety of literary factors; and the Gospels were written for entirely different purposes in a quite different social context, where there was an even greater concern for accurate transmission of a religious heritage.
Nevertheless, oral tradition is clearly one of the pertinent issues and needs to be taken into consideration.