Literary Freedom and the Hellenistic Biographer/Historian
Those who do not believe the New Testament gospels provide much reliable historical information about Jesus often point to variations in the wording of sayings as they appear in different gospels, or to differences in the order of events between gospels. For example, when Jesus is baptized by John, a voice from heaven speaks, but the words differ slightly in Matthew and Mark (Luke agrees with Mark).
Matthew 3:17 - And a voice from heaven said, “This is my Son, the Beloved, with whom I am well pleased.”
Mark 1:11 - And a voice came from heaven, “You are my Son, the Beloved; with you I am well pleased.”
This sort of difference delights detractors of the gospels and perplexes the faithful. It would be pretty hard to argue that the voice from heaven said the same sentence twice in slightly different ways (though I expect this argument has been made somewhere). No, it seems more likely that Matthew and Mark use slightly different words for the same vocal event. If Matthew was using Mark, he made a few changes. (Or it happened the other way around.) Does this prove that one of the gospels is wrong? Does this mean that either Matthew or Mark was a sloppy historian?
Not if we see them in terms of their own time and culture. Yes, we expect historians and biographers to quote their sources with precision. My friend Ronald C. White Jr., for example, wrote a highly acclaimed study of Abraham Lincoln's second Inaugural, Lincoln's Greatest Speech. If Ron had misquoted Lincoln's words, or paraphrased then and put them in quotation marks, Ron would have been blasted by critics. In fact, his book would never have been published.
Yet in the ancient world, before there were transcripts, tape recordings, and podcasts, biographers and historians exercised greater freedom in paraphrasing or slightly altering spoken words for stylistic reasons. Quotation marks didn't exist in Greek of the first-century A.D. A good historian, if he knew that a character had made a speech at a certain time, would get available information about that speech and then write the speech with his own words. Nowadays, a historian who did this would be considered sloppy at best, or even dishonest. (Remember the case of Jayson Blair, not a historian, but a reporter for the New York Times. He disgraced the Times and himself by, among other things, making up quotes that his sources could have side, but didn't in fact say.)
So, assuming for a moment that Matthew used Mark as a source, if we evaluate Matthew according to today's standards, then we'd say he's not very reliable. Yet this sort of anachronistic approach is unhelpful, not to mention unfair to Matthew. For reasons of style or story, Matthew was doing what historians or biographers in his day were expected to do. Nobody would have accused him of falsehood. The proof of this is obvious and, I think, incontrovertible. Both Matthew and Mark were accepted as authoritative in the early church, even though there are many variations in wording such as we find in the baptism of Jesus, or the ordering of events, etc. The early Christians didn't see this as a problem because that's what they were accustomed to in their biographical and historical writings.
Biblical scholars sometimes make a helpful distinction between the ipsissima vox (his own voice) and the ipsissima verba (his own words) of Jesus. In most cases, the gospel writers sought to preserve the ipsissima vox of Jesus, not the ipsissima verba. Of course since Jesus spoke Aramaic as his primary language, and since the gospels were written in Greek, they almost never preserve Jesus's actual words. An exception would be Jesus's provocative use of Abba (Aramaic for "father") in addressing God, and other places where the gospels record the Aramaic words of Jesus.
source
http://www.markdroberts.com/htmfiles/re ... liable.htm