The “many raised saints” story is an interesting one. I have a few pieces on the web concerning it and the questions it raises:
One interesting tidbit about the tale of the “many raised saints” found only in Matthew is the probable insertion of the phrase “after his resurrection” which appears to have been inserted so awkwardly into the Greek that it makes the sentences read as though the tombs were opened and the saints raised at Jesusʼs death, but then they lingered about until “after his resurrection” a day and a half later when they finally “entered the holy city.”
Some of course donʼt think that those two little verses about the anonymous “many raised saints” are historical at all but merely midrash added by Matthew, just as Matthew appears to have added incidents in Jesusʼs birth and childhood filling in gaps in knowledge with tales composed to add understanding in a similarly midrashic fashion. (One prominent inerrantist scholar was voted out of the Evangelical Theological Society in the 1980s for acknowledging that there was indeed a case to be made for Matthewʼs use of midrash in his telling of the Jesus story.)
As for inerrantist Christian apologists on the web who acknowledge the ancient use of midrash and even pesher to help try and explain the way some Gospel authors stretched the meanings of Old Testament verses to suit their prior view of “who Jesus was,” please read “The Fabulous Prophecies of the Messiah” which includes comments from Christian apologists at the end.
On this topic of the Gospel authorʼs use of midrash and pesher, even J. P. Holding has listed it among “leading Christian myths” that “OT prophecy fulfillment is a good apologetic. It actually isnʼt useful in the way it was at first. We need to understand (as do Skeptics) Jewish exegesis of the first century. It is not so much that the OT predicted the NT events as that the NT writers looked at history and sought OT passages that echoed what they had seen. This does not mean that there is not actual predictive prophecy at all (for even then God may have orchestrated the pattern) but rather that we cannot present an apologetic on this basis as we normally have; or else we are forced into a corner of explaining ie, why the NT allegedly uses OT passages “out of context.”
Personally, I suspect that the ancient world was generally more mysterious and wondrous than todayʼs and average people were more capable of believing stories or weird strange tales, and capable of repeating them and embellishing them as well. The story of many raised saints, the story of a bodily ascension, the story of a resurrection. I donʼt doubt that Christians were motivated in their beliefs, nor that Christians were motivated to compose not one, but three additional variant endings to Markʼs Gospel, none of them apparently original to that Gospel, and continued to compose additional Gospels and Acts. Truth telling does not seem to have been as important as convincing themselves and others of their beliefs. But certainties are more difficult to come by once Christianity began being examined by more rigorous standards. Historians are not easily cowed by partisan stories of miracles, or by miraculous partisan tales of how various religions allegedly began. Jerusalem itself was turned into rubble in 70 A.D. but the Romans, rubble such that Josephus pointed out if they hadnʼt left the towers of the city standing, one might even doubt that such an immense proud city such as Jerusalem ever had stood on that same spot. So thereʼs no evidence, and no non-partisan writings aside from Josephusʼs mention of Jesus, and even he would have gotten his brief paragraph of info from partisan believers not from actually having seen Jesus himself. The Gospels themselves are written without the authorʼs identifying themselves, and one could read all of the inerrantist and non-inerrantist historians one wants to try and guess who wrote them, and remain uncertain. (And I say that having read Holdingʼs collection of arguments for traditional authorship.)
Nuff said for now, I doubt any single argument can change another personʼs mind that has built up connections with other arguments in a web-like fashion over time, or relieve them of the doubts they may have.