Augustine wrote this book as an argument against those who claimed that alleged discrepancies between Matthew, Mark, Luke and John (often called the “synoptic problem”) invalidated their accounts. He took for granted that the order of the gospels in the New Testament was the order in which they were composed and was the first to recognize a direct literary dependence of one synoptic gospel on another. He maintained that the seeming differences, the additions and omissions were meant to reflect the different themes stressed by each author.
Augustine's view, which became the prevailing opinion in western Christian tradition, is that:
* Matthew wrote the basic story of Jesus' life;
* Mark condensed Matthew;
* Luke edited Matthew and Mark, omitting passages they covered;
* John wrote to fill in what the others omitted.