During the nineteenth century, leading German theologians began an in-depth study called “the quest for the historical Jesus.” They distinguished between what they called “the Jesus of history and the Christ of faith.” By this expression they meant there exists a disparity between these two concepts. By the phrase, “Jesus of history,” they meant Jesus of Nazareth who can be examined from such documents as the New Testament gospels in accordance with certain criterion that historians establish for determining historical authenticity. By the phrase “Christ of faith” they meant the Jesus preached by the church. They meant “Jesus of history” as the Jesus who can be verified by their criterion of historicity, and by the “Christ of faith” they meant a fictional representation of Jesus that was concocted by the church.
Here is a paragraph about this subject from my book, The Restitution of Jesus Christ (2008): “Although it took a while for people to learn about it, no one sounded the death knell of the Old Quest [for the historical Jesus] more than did German dogmatic theologian Martin Kahler (1835-1912). He wrote an essay, first published in German in 1892, in which he took up the subject of the quest for the historical Jesus, framing it with Strauss’ two expressions—“the Jesus of history” and “the Christ of faith.” Recall that the former referred to the historically-authentic, pre-Easter Jesus, the latter to the faith proclaimed by the church. This Christ of faith, also called “proclamation” (Gr. kerygma), centered on identifying the post-Easter Jesus as “God” and emphasizing soteriology. Kahler contended, as Strauss had, that these two concepts are in complete discontinuity and that a choice must be made between them. Opposite of Strauss, Kahler’s choice was, “The real Jesus is the preached Christ.” But Kahler injected a red herring by alleging that the quest cannot produce a biography of Jesus that meets modern standards. With this argument he overthrew “the Jesus of history,” alleging that it is impossible to ascertain Jesus from the gospel records. Kahler’s position would eventually prove tenuous because it completely disconnected the Christian faith from the One whom most Christians regarded as its Founder, and it raised doubts about the significance of the real Jesus.”
This scholarly “quest for the historical Jesus” is still ongoing. It is also called Life of Jesus Research. Those scholars who specialize in such studies are called Jesus Researchers.In my (I hope humble) view, those early German theologians had both truth and error. Those who denounced the church’s proclamation about “the Christ of faith” were right in saying the church got it wrong in declaring that Jesus was God since I do not think that is what the Bible says about Jesus. But these rationalist scholars also got it wrong by throwing out so much of the NT gospels as they applied their criterion of historicity to them. Their result was a Jesus who did not do miracles, never claimed to be Israel’s Messiah, and did not rise from the dead, which to me is a fictional Jesus as well.
In contrast, I think Kahler was right in affirming everything the church had preached about Jesus except that he was wrong to believe, as the church has proclaimed, that the NT gospels say Jesus is God.
So, since I think there is both truth and error in this expression–“the Jesus of history and the Christ of faith”–I would like to change it to reflect what I think more accurately describes the disparity that those scholars attempted to present. In doing so, I accept that the NT gospels present Jesus as he truly existed, so that it is true history. Here is my statement: “the biblical Jesus versus the Christianized Christ.”
In conclusion, what I’m saying is that I believe the church has been right about all it has proclaimed about Jesus except that it has been wrong in declaring he was God.
 Martin Kahler, The So-called Historical Jesus and the Historic, Biblical Christ , tr. Carl E. Braaten (Philadelphia: Fortress, 1964).
 D.F. Strauss, The Christ of Faith and the Jesus of History , tr. and ed. L.E. Keck (Philadelphia: Fortress, 1977).
 However, the expression “Christ of faith” seems inadequate. It suggests no more than belief that Jesus is the Christ whereas it is intended to refer to “the proclaimed, post-Easter Christ,” who was declared as God.
 M. Kahler, The So-Called Historical Jesus and the Historic, Biblical Christ, 66.