I'm thinking this idea of a spiritual resurrection comes from Dan. 12:1-3 (just like the "Son of Man" idea comes from Dan. 7:13-14).
At that time Michael, the great prince who protects your people, will arise. There will be a time of distress such as has not happened from the beginning of nations until then. But at that time your people—everyone whose name is found written in the book—will be delivered. Multitudes who sleep in the dust of the earth will awake: some to everlasting life, others to shame and everlasting contempt. Those who are wise will shine like the brightness of the heavens, and those who lead many to righteousness, like the stars for ever and ever.
I turned around to see the voice that was speaking to me. And when I turned I saw seven golden lampstands, and among the lampstands was someone like a son of man, dressed in a robe reaching down to his feet and with a golden sash around his chest. The hair on his head was white like wool, as white as snow, and his eyes were like blazing fire. His feet were like bronze glowing in a furnace, and his voice was like the sound of rushing waters. In his right hand he held seven stars, and coming out of his mouth was a sharp, double-edged sword. His face was like the sun shining in all its brilliance.
When I saw him, I fell at his feet as though dead. Then he placed his right hand on me and said: “Do not be afraid. I am the First and the Last. I am the Living One; I was dead, and now look, I am alive for ever and ever! And I hold the keys of death and Hades.
But our citizenship is in heaven. And we eagerly await a Savior from there, the Lord Jesus Christ, who, by the power that enables him to bring everything under his control, will transform our lowly bodies so that they will be like his glorious body.
When the dead rise, they will neither marry nor be given in marriage; they will be like the angels in heaven.
1 Peter 3:18:
He was put to death in the body but made alive in the Spirit.
So I'm starting to suspect that perhaps Mark had an original ending with a spiritual resurrection of Jesus (with perhaps even an appearance to Judas?) and it was removed (and then altered with the Long Ending) as a way of countering any appearance of Docetism. But if this was the case, then why weren't Paul's letters similarly altered? I've wondered about that anyway. How did the idea of a physical resurrection emerge in a religion that regards Paul's letters (and 1 Peter) as scripture? I don't know, but somehow the two ideas have managed to co-exist. Perhaps it was easier to overlook Paul (and 1 Peter) than the ending of Mark?
And the proof is the in the pudding. Jesus himself says in Mark, "When the dead rise ... they will be like the angels in heaven." Case closed, in my view. And if there is a physical resurrection, then why isn't Jairus' daughter in Mk. 5:35-43 thought of as being resurrected? Why aren't any of the people who were physically raised from the dead in the OT thought of as being the "first fruits" of the resurrection? Why aren't the dead people who "came out of the tombs after Jesus’ resurrection and went into the holy city and appeared to many people" in Mt. 27:53 thought of as being resurrected (or are
they? What do you suppose happened to them? Did they ascend to heaven like Jesus? Is this
the "transformed" resurrected body that Paul talks about?)?
No, I think the resurrection at the End Time is spiritual, like Paul and Peter (and Daniel and Jesus) say, and that somehow, despite this (I would guess it was in response to Docetism), this idea became uncool and was supplanted by the idea of a physical resurrection (as per Mt. 28:9, Lk. 24 and Jn. 20).
You know in spite of all you gained, you still have to stand out in the pouring rain.