Here is a typical example that I found on an apologist’s blog:
When I say embarrassing I mean if the account was fictional, the writers would have never included such an event. An example of embarrassment is to make a fool out of Peter, the brave leader of the disciples. In the Gospels we read that under pressure and fearing for his life, during the trial of Jesus just before he was crucified, Peter denied knowing who Jesus was; in fact he did it 3 times. Peter, the powerful disciple of Jesus, is shown to be a coward at the time of Jesus’ arrest and greatest need. Peter later redeems himself, lives a courageous life, and eventually is crucified upside down for his belief in Jesus. However, the Bible doesn’t pull any punches in showing at the trial of Jesus, Peter was a coward! There are many embarrassing moments in Matthew, Mark, Luke, John, and Acts so many so, that historians say this is evidence for the historical accuracy of the Bible or at least these books.
I think that this is an embarrassingly bad argument. I am sure that this Christian has heard countless sermons about the transformative power of the gospels that cite the change in the apostles. In fact, the same Christians who make this argument usually cite the apostles’ transformation from bumbling cowards to dynamic preachers as proof of the reality of the resurrection. Far from being embarrassing, the earlier ineptitude of the apostles is a indispensable element of the narrative. If Peter had acted courageously and powerfully before the resurrection, the story wouldn’t make any sense and the gospel message would be much less persuasive.
Christian apologists tend to rely on the criteria of embarrassment an awful lot. It is very convenient for them because it does not require any corroboration from outside sources. Nevertheless, if we can see that an element serves an important function in the narrative structure, we cannot conclude that the author would never have invented it even if it can be characterized as embarrassing. I think we also have to take into account the possibility that the author might have had a reason for inventing the detail that we cannot now discern. In the case of the apostles’ bumbling, however, the reason for including it is so obvious that I find it hard to believe that anyone can argue for the criteria of embarrassment with a straight face.