I have argued that the agreement that exists between the seven gospel sources concerning the Minimal Jesus Hypothesis, could be explained on the basis of the common cultural idea of a ‘Messiah’. I conceded, however, that the crucifixion of the Messiah was not a part of the expectation of first century Palestinian Jews, but pointed out that the crucifixion of Jesus and surrounding events are described only in Mark and the Gospel of Peter, and not in the other gospel sources that Ehrman points us to. Thus, there is no agreement between gospel sources concerning the crucifixion of Jesus.
In any case, the Minimal Jesus Hypothesis could be transmitted, for the most part, by a single sentence:
Jesus the Messiah was crucified.
Thus, there is no need for a common textual source to explain the agreements between the various gospel sources, nor a need for an actual historical Jesus to explain these agreements.
In conceding that the common cultural idea of a ‘Messiah’ did not include the crucifixion of the Messiah, I was reflecting the general concensus of N.T. scholars that the idea of a suffering and dying Messiah was an invention of the early Christians, which departed from previous Jewish beliefs:
According to Klausner’s generally held view, the idea of messianic suffering, death, and resurrection came about only as an apology after the fact of Jesus’ death. In this view, it is simply a scandal for Christian messianic thought that Jesus was scourged and humiliated as a common rebel, despite the fact that he was the Messiah….After the Messiah Jesus’ humiliation, suffering, and death, according to this view–held by many Christian thinkers and scholars as well as Jewish ones–the theology of Jesus’ redemptive, vicarious suffering was discovered, as it were, in Isaiah 53, which was allegedly reinterpreted as referring not to the persecuted People of Israel, but to the suffering Messiah…
(Daniel Boyarin, The Jewish Gospels, p.130-131; referring to The Messianic Idea in Israel by Joseph Klausner).
Boyarin, however, argues that the idea of a Messiah who experiences redemptive, vicarious suffering was a Jewish idea derived from midrash on the book of Daniel and Isaiah:
The notion of the humiliated and suffering Messiah was not at all alien within Judaism before Jesus’ advent, and it remained current among Jews well into the future following that–indeed well into the early modern period. The fascinating (and to some, no doubt, uncomfortable) fact is that this tradition was well documented by modern Messianic Jews, who are concerned to demonstrate that their belief in Jesus does not make them un-Jewish. Whether or not one accepts their theology, it remains the case that they have a very strong textual base for the view that the suffering Messiah is based in deeply rooted Jewish texts early and late. Jews, it seems, had no difficulty whatever with understanding a Messiah who would vicariously suffer to redeem the world. Once again, what has been allegedly ascribed to Jesus after the fact is, in fact, a piece of entrenched messianic speculation and expectation that was current before Jesus came into the world at all. That the Messiah would suffer and be humiliated was something Jews learned from close reading of the biblical texts, a close reading in precisely the style of classically rabbinic interpretation that has become known as midrash, the concordance of verses and passages from different places in Scripture to derive new narratives, images, and theological ideas. (The Jewish Gospels, p.133)
While there is no crucifixion per se in the book of Daniel nor in Isaiah, if the idea of a Messiah who would be humiliated and would suffer vicariously for the sins of others was derived or derivable from Daniel and Isaiah by first century Palestinian Jews, then, given that crucifixion was clearly one of the most humiliating and suffering-inducing forms of execution used by the Romans at that time, it is not a big stretch to see the crucifixion of Jesus as being based upon the idea of a ‘Messiah’ as shaped by Jewish midrash on Daniel (chapter 7) and Isaiah (chapter 53).