So how do historians sort through the gospels for the historical Jesus?
First, it is important to understand the background which produced the NT texts, and this means understanding first-century Judaism. Next, it is important to understand the nature of the texts in the NT, which consists mainly of gospels and letters.
Lets start with the letters of Paul. Paul wrote letters to Christian communities advising them, and his letters were saved and copied because of his status within the Jesus community. These letters are not overly concerned with transmitting information about Jesus himself, because they are addressed to people who already know the tradition. However, Paul speaks of the Jesus tradition being formally transmitted to him, and he talks about meeting with the people who personally knew Jesus.
Then there are the gospels. I have already said they are a type of ancient history/biography. They are recordings of oral traditions. Therefore, the most important part of sorting through the gospels for historical information is understanding the method of transmission of these traditions.
First, when these texts were written, people who knew Jesus were still alive. This in itself does not mean that the oral traditions upon which the gospels were based were accurate. Methods of oral transmission vary vastly between cultures and within the same culture, depending upon the type of information being transmitted (for example, rumors vs. religious material). It is important to note, however, that even oral traditions transmitted over hundreds of years that are not designed to reliably transmit history retain nuggets of historical truth. Take, for example, the Iliad. Here is an story from oral traditions going back hundreds of years, which was told for entertainment purposes and without thought for historical accuracy. Yet we know from archaeological records that even in this work historical nuggets are to be found. The gospels were formed from a vastly more reliably transmitted tradition, and were written down within a generation or two after Jesus died, leaving far less room for change.
I may get into more detail about orality within the Jesus tradition later, but right now I will refer those interested in learning how accurately the sayings/stories in the Jesus tradition were transmitted to two excellent works:
Memory and Manuscript: Oral Tradition and Written Transmission in Rabbinic Judaism and Early Chiristianiyt by Birger Gerhardsson
And
Jesus and the Oral Gospel Tradition ed. Henry Wansbrough (with contributions from 15 scholars).
And now for those interested in historical Jesus studies by critical non-christian scholars:
Bart D. Ehrman, an ex-Christian who lost his faith when he began studying the gospel in detail wrote a short book on his view of the historical Jesus titled Apocalyptic Prophet of the New Millenium. I personally think he is wrong on many points, and his work is mostly a rehash of Schweitzer, but for those looking for anti-Christian views of the historical Jesus by actual scholars, he is one.
J. D. Crossan, an ex-Catholic priest who believe Jesus body was devoured by dogs wrote The Historical Jesus. Although some of Crossans work has merit, I consider most of it way out there with little to back it up, but again here is someone with expertise writing about the historical Jesus.
Geza Vermes is a Jewish scholar with many publications on the historical Jesus, but see in particularly his book Jesus and the Jews: A Historians Reading of the Gospels.
I can give more if need be.
However, if you want a very good up-to-date book on the historical Jesus and arent prejudiced by reading from a Christian historian, see James Dunns Jesus Remembered.
First, it is important to understand the background which produced the NT texts, and this means understanding first-century Judaism. Next, it is important to understand the nature of the texts in the NT, which consists mainly of gospels and letters.
Lets start with the letters of Paul. Paul wrote letters to Christian communities advising them, and his letters were saved and copied because of his status within the Jesus community. These letters are not overly concerned with transmitting information about Jesus himself, because they are addressed to people who already know the tradition. However, Paul speaks of the Jesus tradition being formally transmitted to him, and he talks about meeting with the people who personally knew Jesus.
Then there are the gospels. I have already said they are a type of ancient history/biography. They are recordings of oral traditions. Therefore, the most important part of sorting through the gospels for historical information is understanding the method of transmission of these traditions.
First, when these texts were written, people who knew Jesus were still alive. This in itself does not mean that the oral traditions upon which the gospels were based were accurate. Methods of oral transmission vary vastly between cultures and within the same culture, depending upon the type of information being transmitted (for example, rumors vs. religious material). It is important to note, however, that even oral traditions transmitted over hundreds of years that are not designed to reliably transmit history retain nuggets of historical truth. Take, for example, the Iliad. Here is an story from oral traditions going back hundreds of years, which was told for entertainment purposes and without thought for historical accuracy. Yet we know from archaeological records that even in this work historical nuggets are to be found. The gospels were formed from a vastly more reliably transmitted tradition, and were written down within a generation or two after Jesus died, leaving far less room for change.
I may get into more detail about orality within the Jesus tradition later, but right now I will refer those interested in learning how accurately the sayings/stories in the Jesus tradition were transmitted to two excellent works:
Memory and Manuscript: Oral Tradition and Written Transmission in Rabbinic Judaism and Early Chiristianiyt by Birger Gerhardsson
And
Jesus and the Oral Gospel Tradition ed. Henry Wansbrough (with contributions from 15 scholars).
And now for those interested in historical Jesus studies by critical non-christian scholars:
Bart D. Ehrman, an ex-Christian who lost his faith when he began studying the gospel in detail wrote a short book on his view of the historical Jesus titled Apocalyptic Prophet of the New Millenium. I personally think he is wrong on many points, and his work is mostly a rehash of Schweitzer, but for those looking for anti-Christian views of the historical Jesus by actual scholars, he is one.
J. D. Crossan, an ex-Catholic priest who believe Jesus body was devoured by dogs wrote The Historical Jesus. Although some of Crossans work has merit, I consider most of it way out there with little to back it up, but again here is someone with expertise writing about the historical Jesus.
Geza Vermes is a Jewish scholar with many publications on the historical Jesus, but see in particularly his book Jesus and the Jews: A Historians Reading of the Gospels.
I can give more if need be.
However, if you want a very good up-to-date book on the historical Jesus and arent prejudiced by reading from a Christian historian, see James Dunns Jesus Remembered.