THE SYNOPTIC PROBLEM
PAPIAS was the first to say that there was an oral collection of
sayings of Jesus before the Gospels were written. This implies that
the Gospels could not be chronogically written, nor accurately
transmitted. This assumed collection of sayings on Papias'
testimony, whether in written or oral form is the basis for the
assumption that there is a Q
source. (German quelle -source)