The Gospel of Luke and the Book of Acts are closely related. Written by the same author and for the same purpose, both were addressed to a Christian named Theophilus and were designed for the purpose of presenting to him a complete and well authenticated narrative of the early history of the Christian movement. In the introductory paragraph of the gospel, Luke tells us that many lives of Jesus were written on the basis of eyewitness reports. He does not find these narratives satisfactory in all respects and so has set himself the task of examining the records and writing a new account that will establish for all interested parties the certainty of the things about which Christians were instructed.
The first paragraph in Luke's gospel is especially informative to readers of the New Testament, for it describes the way in which the two narratives attributed to Luke came to be written. Luke evaluated the materials he wanted to use and then supplemented them in whatever manner seemed to him to be the most appropriate. In writing his gospel, he did not simply piece together bits of information that he gathered from different sources; rather, his own contributions include selecting and organizing these materials, along with whatever interpretation was necessary to make a complete and unified narrative.
We can be quite certain that Luke made use of at least three different sources: the Gospel of Mark, the Q source, or "The Sayings of Jesus," and a third source that is usually designated as L to distinguish it from other biographies. The Gospel of Matthew may have existed by the time Luke wrote his account, but nothing indicates that Luke knew anything about Matthew or made any use of it. Luke was a companion of Paul, and he was quite familiar with the different interpretations of the life of Jesus held by different groups within the Christian community. His purpose was to minimize the differences between the various groups and thus promote harmony within the church. He was aware, too, of the criticisms concerning Christianity that were being made by people who were outside the church, and he especially wanted to make an effective reply to those who claimed that Jesus was a revolutionist and hence an enemy of the Roman government. By giving to his readers an authentic account of the life and teachings of Jesus, Luke could show that the charges made against Jesus were false. He was quite sure that if people knew of the kind and sympathetic way in which Jesus met individuals, they would be won by the attractive power of Jesus' wonderful personality. Luke possessed rare ability as a writer, and it has often been said that his gospel is the most appealing of all those in the New Testament.
