"Chinese whispers" effect: every repetition and re-telling is liable to produce a change, however slight.
There is a story that, some 20 years after the death of Abraham Lincoln in 1865, admirers of the great man set out to record oral memories of what he had said and done. They talked to relatives, neighbors, servants and other close associates, carefully noting everything they were told. But when they came to put the oral archive together to make a coherent portrait they discovered that there were so many contradictions and discrepancies, particularly in the recollection of Lincoln's exact words, that it was impossible to produce a reliable account. The project was abandoned.
The problem is not new. The Greek historian Thucydides, writing in the fifth century BCE, described how he tackled the task of reporting the speeches made by various leaders in the Peloponnesian war:
"It has been difficult to recall precisely the words they actually spoke. This is the case whether they were speeches I myself heard or whether they were words reported to me from other sources. As a consequence, the various speakers were made to say what was appropriate, as it seemed to me, to the subject, although I attempted to stick as close as possible in every case to the general scope of the speech."
This needs to be remembered when someone is citing religion as their foundation for truth. Take Jesus of Nazarene, for example: Jesus spoke in one language, a local dialect of Aramaic, and the written record of what he said was made in another, Greek. Chinese whispers circulating around a room in a single language usually emerge with significant changes. Chinese whispers transmitted in a single language through two or more decades (earliest written reference of Jesus was Paul's letters around 50 CE. The four gospels were written starting in the 80s) are even more likely to emerge corrupted. How much more so, then, when the whispers originate in one language, rural and oral, and end up twenty years later in a quite different one, global and literary? By then it will surely be something of a miracle if they still convey the authentic gist and spirit, let alone the precise meaning and intonation, of the original.
When we read that Jesus said "Blessed are the peacemakers, for they shall be called the children of God", we need to remember that we are reading a sixteenth century English rendering of what was considered by the translators to be the best version available of centuries old Greek texts, which themselves relied on someone's reported memory of what had been spoken twenty or more years earlier in an Aramaic dialect.
Put that in your pipe and smoke it! I understand it is hard to hear facts that contradict personal beliefs deeply rooted within a person, however, the search for truth is an arduous process and a surprising one. Beliefs can be debated. Facts can not.
(Referenced David Boulton's Who on Earth was Jesus?)