I found this quote from James M. Robinson's book, The Gospel of Jesus:
It is not the resurrection stories that make Easter, but the other way around. It was his disciples experiencing Jesus still making his point, as a gospel still real even after his death, that created the Easter stories. So that is the only valid form of Christian faith today. Easter faith is taking Jesus at his word, that God is a heavenly Father who really cares, who reigns for us and through us in our daily lives. Easter was not just the launching of another religion of a dying and rising God, of which the ancient world had already too many. It was the disciples' renewed experience of Jesus saying again that God continues to be there for us, and for others through us, in spite of the horror of "Good" Friday. That is indeed good news, the gospel of Jesus risen from the dead. (p.207)I like this passage because I think it gets to the heart of the meaning of progressive Christianity. The first sentence summarizes an essential point: Easter is not about the mythological Easter narratives that appeared in Matthew, Luke, and John; rather, the mythological narratives are about Easter. Think about this for a second. What he is saying--and I agree--is that the literal truth of the narratives of Jesus walking around after he died is irrelevant to the Christian faith. It isn't those narratives that matter, but what those narratives point to.
And what those narratives point to is this--that the core of theological message, which Jesus did not only teach but lived out as radically and fully as possible--rang true for those early disciples and actually continued on, despite Jesus having died. And the message that rang true was, as the above quote indicates, "that God is a heavenly Father who really cares, who reigns for us and through us in our daily lives." Particularly, "through us in our daily lives" means that seeking the Kingdom of God isn't about obtaining some reward in the afterlife, but this Kingdom is in fact here with us now, whenever choose to live out God's will among us. God isn't a remote supernatural being outside the everyday world we experience, but acts through us in our own actions.
After Jesus died, his followers came to the conclusion that Jesus's life and message about the Kingdom of God were still valid, even if Jesus himself had been executed for having proclaimed it. They continued to experience Jesus calling them forth even though he was physically gone from their lives. This was the Easter experience--this was the "resurrection". Only later did the stories of an empty tomb and of Jesus walking on the road to Emmaus, and so forth, emerge to give a narrative framework to this Easter experience. But it was Easter that came first, before those stories emerged.
This is very much the inverse of what that bastion of orthodoxy, the Nicene Creed proclaimed. This creed focused almost exclusively on the supposedly miraculous events that bookended his life on earth while ignoring the message and lifestyle that he proclaimed in between those bookends of birth and crucifixion. Thus Christianity became distorted by this creed, which presumed that Jesus's ministry on earth was merely a prelude that pointed to his resurrection. Instead, let us consider that Jesus's resurrection pointed back to his life. His message lives on, even if Jesus is dead.