One argument I've heard against Christianity quite a few times is that early Christians copied earlier "groups" (can't think of the proper word). Doesn't this article seem to confirm that?
In all reality shouldn't Christians be a little worried that the Jesus they have grown to love and worship could be a fake who tricked people into thinking he was the Messiah?
How many different concepts in Christianity are supposed to have been borrowed from how many different sources now? Wasn't the Christian resurrection claim supposed to have been derived from pagan religion X? Or was it pagan religion Y? Or Z? Or wasn't it from some Jewish source? Or maybe it was from this latest Jewish source that's being discussed. Or maybe it's another pagan or Jewish source that will be found a few years from now. Apparently, just about everything in Christianity was borrowed from just about everybody.
I realize that critics don't make that claim. And I realize that one critic isn't responsible for what another critic argues. But I'm exaggerating to make the point that the argument for Christian borrowing seems to be largely overused and unverifiable. It's Play-Doh in the hands of a lot of critics who use it in a lot of different, and contradictory, ways.
If we grant all of the critics' assumptions about what the tablet says, it does have some significance in weakening the case for Christianity. But not nearly the level of significance that some people are suggesting. If the concept of an individual resurrection prior to the general resurrection, or a resurrection of a suffering Messiah in particular, is found in this tablet, then that concept isn't as unique to Christianity as some people have argued.
I'm reminded of a comment Eric Svendsen made a few years ago, regarding the perpetual virginity of Mary. Some Roman Catholics were suggesting that they had found a document that in some way supported their reading of Matthew 1:25, although the vast majority of the relevant literature was still contrary to their position, even if their interpretation of this one document were granted. Eric responded by summarizing their argument as something like: "Our position is no longer impossible to defend! Now it's just nearly impossible to defend!"
As one of the commenters on Ben Witherington's blog notes, we have a large amount of literature from the centuries leading up to Jesus' birth, from His contemporaries, and from the generations that followed shortly after. Finding a concept in one tablet from that era doesn't change the fact that it's absent from and contrary to the vast majority of the sources of that time. If the critics' reading of this tablet is correct, we still have to ask how likely it is that the tablet or its ideas influenced early Christianity and what the nature of that influence was.
The argument for Jesus' resurrection involves many lines of evidence. The uniqueness of the resurrection concept is just one line among others, and it's one that some Christians don't even use. And the resurrection is one argument for Christianity among others. Critics would still have to address fulfilled prophecy, the other miracles of Jesus, and the miracles of the apostles, for example. This tablet doesn't make a major difference for or against Christianity.