Overview of an elegant solution to the Synoptic Problem

"Everything should be made as simple as possible, but no simpler."
- attributed to Albert Einstein
The elegance of the radical Three-Source Theory presented here is two-fold. Firstly it combines the best features of the prevailing Two-Source Theory together with the best features of one of its main rivals: the Farrer Theory. Secondly this solution brings to light a document known for centuries as 'the logia' (the sayings of Jesus), but only now successfully reconstructed and shown to have been a majestic piece of first-century Semitic poetry.
  1. The documents

    The relevant documents [1]  are the logia and the gospels of Mark, Matthew and Luke, written in that order, and with each author having had access to a copy of each earlier document. In other words the logia was a source for all three synoptic gospels, Mark was a source for both Matthew and Luke, and Matthew was a source for Luke. [2]  Thus the theory involves three sources: the logia, Mark and Matthew. Hence the name "Three-Source Theory".
  2. The logia

    The logia was an Aramaic collection of sayings attributed to Jesus, known from the testimony of Papias [3] : "So Matthew [4] made an orderly arrangement of the oracles (Gk: 'logia') in the Hebrew [5]   language, and each interpreted/translated according to his ability". Each of the sayings was in the form of an 'aphorism' (a short pithy saying).
  3. The first gospel

    Mark's gospel was the first written story of the life of Jesus, and the account was adapted and developed by both Matthew and Luke.
  4. The Double Tradition

    The key to the solution of the Synoptic Problem is to recognize that the Double Tradition [6]   was dual-sourced.
  5. The aphorisms

    A majority of the Double Tradition passages derive from the logia. They contain aphorisms,   most of which Matthew and Luke translated independently into Greek. [7]
  6. Where Luke used Matthew

    A minority of the Double Tradition passages derive from Matthew. They represent places where Luke copied and edited some of Matthew's extensions to Mark, such as the Temptations, the Centurion's Servant, the Unclean Spirit, and the Lament over Jerusalem.
  7. Mark's use of the logia

    Mark was more selective than Matthew and Luke in his use of the logia, retaining only about half of its sayings. [8] 
    Among the aphorisms Mark retained from the logia are a few which did not become part of the Double Tradition, such as the one about the camel and the eye of a needle, and the one about paying taxes to Caesar.

Data flow diagram representing the literary dependence of the synoptic gospels

In the diagram below,
3ST data flow diagram

Notes

1. All three synoptic gospels include quotations from books of the Jewish scriptures, especially Deuteronomy, Isaiah, and the Psalms. These are important secondary sources, but as their use is not a distinguishing feature for synoptic theories, there is no value in including them in synoptic theory overviews or synoptic theory diagrams.
2. The scholarly Luke handled the considerable overlap between Matthew and his other two sources by treating Mark as his primary source for structure and narratives, the logia as his primary source for sayings, and the more recent Matthew as a secondary source.
3. As quoted by Eusebius. Papias (ca. 60-130 CE) was the bishop of Hierapolis.
4. Papias was referring to the apostle Matthew, not to the author of the gospel which bears his name. For while the context of the quotation about Matthew in Eusebius shows clearly that he took "Matthew" to have been the writer of what we know as the gospel of Matthew, we should not assume that this quotation was originally in the context in which Eusebius placed it.
5. In Papias' time people who wrote in Greek would often use "Hebrew" to mean either Hebrew or Aramaic.
6. The Double Tradition consists of passages which are common to Matthew and Luke but not to Mark.
7. In a few exceptional cases Luke appears to have made use of Matthew's translation.
8. Perhaps the surprise here is that Mark retained versions of as many as half of the logia sayings, for his hero Paul had often by implication belittled their importance (1 Cor 2:1-2; 2 Cor 5:14-16; Gal 6:14).