This shall be a brief note, following on from a comment earlier made. It needs must be proceeded by acknowledging I am neither a theologian nor a biblical scholar.
The genesis of this idea was a discussion of whether an individual today could know anything about Jesus. (To avoid an obvious complexity, it is assumed that there was a single actual individual whose variation of Judaism is the origin of Christianity). It seemed an obvious retort to base any claims about this Jesus on the Christian Scriptures. As such, the claim would take the form ‘I know x about the Scriptural Jesus’ (for, ‘I know that Scriptural Jesus regularly employed metaphor’).
A problem with this stratagem (for want of a better word) is that it seems difficult to actually construct a ‘Scriptural Jesus’. Reliant on the accepted Gospels – those of Matthew, Mark, Luke, and John – it could be argued that there are at least four different ‘Scriptural Jesuses’. How so? Each of the ‘authors’ (whose existence and nature are currently contested issues) creates a different Jesus in their text. I am, at this point, going to have to reach for authority. I first recall encountering the idea that the Gospel authors presented different ‘aspects’ of Jesus in Studies of Religion nearly a decade ago, and have since discussed the idea with a couple of theologians who have accepted it. It’s theological basis is that, on consideration of the Gospel texts, there are differences between the Jesuses in terms of their teaching styles and, where comparison is possible, their actions. It does not seem too great a step from a claim that Mark presents different aspects of Jesus to John (and I would like to be able to make evidential reference to the texts, but I do not have them at hand) to a claim that they actually present different Jesuses. This takes the 'character' presented in the Gospel as a Jesus distinct from the Jesus character protrayed in the others. It is akin to a step that classicists seem willing to make in regard to Plato, where there is an accepted distinction between the early Platonic Socrates and the later Platonic Socrates. It is also akin to the acknowledgement that the Socreates of Plato is different to that of Xenophon.
At its crux, the problem is one of reconciling the differences between the accounts contained in the Gospel. As there are differences, to claim a Scriptural Jesus would require a reconciliation, which in turn would require a justification of the decisions made. As such it may be safer to make claims in regard to the Jesus portrayed in the different texts (returning to the example, ‘Mark’s Jesus regularly employed metaphor’).
As a brief post script, it should be acknowledged that, if there are four different Scriptural Jesuses, then there are more as each Gospel not included in the Christian Scriptures contains a different Jesus.