The different Gospel accounts generally show agreement. Yet, they also show striking divergences. For example, the birth story of Jesus in Matthew and Luke are entirely different while Mark does not record any birth (Matt. 1:18-2:23; Luke 1:5-2:52). Why is this so? Another example is that Matthew and Luke both have genealogies, but the list in each differs and Mark skips a genealogy altogether (Matt. 1:-17; Luke 3:23-28). Again we ask why? Another one is that Matthew's Sermon on the Mount account is longer than the sermon recorded in Luke 6:20-49, but some materials are found in Luke that are not found in Matthew. There seems to be too many inconsistencies. Finally if all wrote of the Passion of Christ, his death and resurrection, why do each contain many differences and no two record exactly the same series of event? These differences are some among many.
One would expect that there shouldn't be any differences on such an important story as the life of Christ. Yet, like a sore thumb these seeming anomalies stick out. How then do we solve this?
The early church was not ignorant of this problem, but there was really no serious attempt to explain it. Since the gospels were treated as authentic and above reproach, interests converged on how they harmonize instead. This led to endeavors to try to unify the gospels as one continuous narrative. This interest was expressed in Tatian's Diatessaron (160 AD).
Then in the year 400 AD, St. Augustine of Hippo wrote On the Harmony of the Evangelists (De Consensu Evangelistarum). His explanation was that the sequence in how they appear in the Bible was the sequence in which they were written. According to him, Matthew was written first, then Mark abbreviated his version from Matthew, and Luke used both to write his. Augustine also believed that each writers did not write without a knowledge that there were others undertaking the same task. Yet each followed an independent path. This was his answer to the synoptic problem.
It was not until the Enlightenment period (1650-1800) that serious work was made. The early proposals to explain the synoptic problem gave rise to five main theories:
1. The Primitive Gospel Theory: German scholar G.E Lessing in 1771, suggested that the three gospels followed an earlier Aramaic gospel that is now lost. He based his theory on an obscure passage in the writings of St. Jerome that stated an existence of a Gospel of the Nazarenes in the 4th century AD. J.G Eichhorn developed this theory and concluded that there must have been several revision of this Aramaic gospel before Matthew, Mark, and Luke wrote theirs. Thus Matthew, Mark, and Luke differs from each other because they followed different revisions.
2. The Oral Tradition Theory: Another German scholar by the name of J.G Herder in 1797 came out with the theory that the gospel was transmitted orally and that there was never any written source prior to the writing of Matthew, Mark, and Luke. He contends that the gospel in general emerged from a frequent telling of it by the disciples and early Christians. This theory was expanded in 1818 by J.K.L Giesler who insisted that the oral transmission of the gospel was originally in Aramaic and as more and more Gentiles were added, a Greek oral tradition emerged. And that it was this transplanting from Aramaic to Greek that brought different emphases, presentations consistent with the needs and interests of the Gentile audience. Thus, Matthew produced his gospel with a Palestinian Jewish emphasis, Mark, under the influence of Peter, wrote a modified Palestinian gospel for Jews in Rome and elsewhere, and Luke, as a companion of Paul, wrote to Gentiles. C.C Torrey argued a form of it in 1933: The Four Gospels.
3. The Fragmentary Theory: in 1817, Friedrich Schleiermacher proposed that a large number of short written accounts in circulation was what the early church had. He held that these accounts were brief records of particular events that had been written by various eyewitness and that years later the writers of Matthew, Mark, and Luke collected these account and formulated their accounts. Therefore because of these fragmentary sources, we find differences in the gospels.
4. The Matthean Priority: That Matthew was the first gospel to be written was a view generally held by the early church fathers. The opinions of St. Iraneaus and St. Origen was that Matthew initially wrote in Hebrew or Aramaic and that it was later on translated into Greek. This is what St. Jerome and St. Augustine also believed. Furthermore, St. Clement of Alexandria wrote that the first gospel was the one with the genealogy. Even so, most modern scholars do not accept this view. Noteworthy proponents of this view are Johann J. Griesbach in 1789, H. Owen in 1764, and William R. Farmer in 1976 (The Synoptic Gospel).
5. The Markan Priority: In 1863 H.J Holtzmann and in 1924 B.H Streeter advocated a Mark first theory. This view is the commonly held view among most scholars today. While it began as a two-source theory, it has expanded into a four-source theory.
This view proposes that Mark wrote first and became the source for Matthew and Luke. Of the 661 verses of Mark, 601 of them are found in Matthew and Luke. Exact wording in Mark are also found in Matthew and Luke. But where they diverged from each other are in particular where Mark seems to exhibit a primitive style of writing to which Matthew and Luke improve the style or clarify the subject matter (cf. Mark 2:4; 7; 13:14). Or when Mark writes in Aramaic and both Matthew and Luke either modify the Aramaic or leave it out. And while for the most part Matthew and Luke follows Mark's outline, a second point of divergence are when Matthew and Luke followed other sources. This has led to the hypothetical Q source, where Matthew and Luke agree with each other outside of following Mark; the hypothetical M source where Matthew has materials particular only to his gospel; and the hypothetical L source, where Luke has materials strictly found in his gospel.
So while scholars argue and try to figure out this synoptic problem we cannot help but point out the obvious result of the one gospel they write about: complementary yet authoritative portrayed of the life of Jesus, rich theological emphases, and God-inspired truths for conducting life. These we can safely and confidently trust and rest on.