A point that Christian apologists sometimes make is that the Resurrection’s veracity is evidenced by the fact that many Christians who said they witnessed it were willing to die for that belief. It is sometimes rejoined, big deal, there are plenty of, say, Muslims now willing to die for their beliefs.
But there’s an obvious difference. The Christian martyrs who claimed to be eyewitnesses to a specific event are different from Muslims who make no similar claim. That is, the first-century Christians were in a position to know if something really happened or not. Their willingness to die for that belief is strong evidence that it actually did.
Suppose the question is whether there is a penny underneath a saucer. Person A looks underneath the saucer and says there is. He is called a liar, and responds, “If there is not a penny underneath that saucer, I will give you $1000.” Now, if you listen to this exchange, you could reasonably conclude that there is probably a penny there, all right, since otherwise why would A make such an offer?
It’s very different if person B makes the same $1000 offer, based not on his own peek underneath the saucer, but instead on other, second- or third-hand, evidence. B’s faith in that evidence may or may not be misplaced, but it is not itself direct evidence in the way A’s faith is.
Addendum: Gary Habermas and Michael Licona make this point in their book The Case for the Resurrection of Jesus (300 n.38).