Research by Robert L. Lindsey has helped clarify the process by which gospel texts were preserved and transmitted. (See the outline of Lindsey’s conjectured process of gospel transmission below.)
Luke desired, he said in his prologue, to present to Theophilus an “orderly” account. Such ordering is to be noted in Matthew and Mark, as well. These attempts at ordering help us understand why so many of the synoptic gospel stories appear in a different chronological order from gospel to gospel.
Matthew, for example, placed Jesus’ teaching on anxiety (Matt. 6:25-34) after Jesus’ words about serving two masters, whereas Luke (Luke 12:22-31) placed the teaching on anxiety after the parable of the rich fool, even though Luke also preserved Jesus’ words about serving two masters (Luke 16:13).