Since I think that we can document that both the empty tomb story and the miracle stories included in the gospels are later additions to the Jesus story, your question actually carries us into the Jesus experience. It was the Jesus experience that caused people to see him as victorious over death and as the messianic figure around which the miracle stories gathered.

I see the primary Jesus experience as being that of a boundary breaker. His humanity and his consciousness seem to me to be so whole and so expanded that he was able to escape the basic human drive of survival that binds so many of us who are less fully developed. Unlike us, he appeared to need no security barrier behind which to hide. He could thus step across the boundaries of tribe, prejudice, guilt and even religion into a new dimension of what it means to be human and this is what caused people to experience God present in him. His call to us is therefore not to be religious but to be human and to be whole.

That is what every gospel symbol, from his miraculous birth to his empty tomb, is seeking to convey, so we read them as doorways into the meaning of God.