Q source
The combined work divides the history of first-century Christianity into three stages, with the gospel making up the first two of these – the arrival among men of Jesus the Messiah from his birth to the beginning of his earthly mission in the meeting with John the Baptist, followed by his earthly ministry with events such as the Sermon on the Plain and its Beatitudes, and his Passion, death, and resurrection (which concludes the gospel story). Most modern scholars agree that the main sources used for Luke were (a) the Gospel of Mark, (b) a hypothetical sayings collection called the Q source, and (c) material found in no other gospels, often referred to as the L (for Luke) source.