Q: Why do most critical and skeptical scholars agree that Mark was written around 70A.D and the other gospels where written after 70 A.D?
A: The arguments for the traditional dating of the Gospels have been aptly compared to a line of drunks reeling arm in arm down the street. Trip up one, and they all collapse.
Since it is generally agreed that Mark was one of the sources used by Matthew and Luke, it follows that if Mark was written around AD 70, then the other Gospels musthave been written later. So the usual dating of the Gospels depends crucially on Mark’s date.
By contrast, if we begin with Luke and Matthew and work backwards, then the date of Mark is pushed back well before AD 70. The evidence that Acts was written prior to AD 70 (e.g., Paul’s being still alive under house arrest in Rome, no mention of significant events during the AD 60s such as the martyrdom of James, the persecution of Nero, the siege of Jerusalem, etc., and the disproportionate emphasis on Paul’s recent voyage to Rome) strikes me as very persuasive. Since Acts is the sequel to Luke’s Gospel, Luke must have been written in the AD 50s, and accordingly, Mark even earlier. Such a dating makes eminently good sense. It is incredible that the early church would have waited for decades before committing the Jesus story on which it was founded to writing.
So why do scholars find the evidence for a later date of Mark so compelling? The answer seems to be that Jesus in his Olivet Discourse describes the destruction of Jerusalem by her enemies, and so Mark’s narrative must date from the time of this event. But this argument cannot bear the weight placed on it. For the distinctive features of the Roman siege of Jerusalem as described by Josephus are conspicuously absent from Jesus’ descriptions of Jerusalem’s predicted destruction. His predictions resemble more closely the Old Testament descriptions of the destruction of Jerusalem in 586 BC by the Babylonian army than descriptions of the Roman destruction in AD 70. Again, this makes such good sense. As a prophet Jesus would naturally draw upon the Old Testament for his predicted judgement upon Jerusalem.
If this argument for a later date of Mark falls, so do all the dates dependent upon it. While the historical credibility of the Gospels in nowise depends on this earlier dating, still such an early date strengthens all the more the case for their historical reliability.
– William Lane Craig