A brother of mine is teaching his students through Revelation and this question came up:
"It says that the Son of Man holds the keys to Hades, what does that mean?"
He gave me permission to repost my response:
It's a good thing you're teaching about Revelation the weekend before the world ends. My primary question is what this would have meant to John the Revealer and the community which he was writing to. Through the preservation of this scripture and our canon tradition, we are also members of that community (from a distance).
The question of where Jesus went between his execution and resurrection is essentially a cosmological issue. To the community, the place where the dead go is Sheol (Hebrew) or Hades (Hellenistic). This is not Hell (in the divine eternal judgment sense), but a "waiting room" for spirits of the deceased until the new age/kingdom of God. Think of Disney's Hercules for a visual. The early Christian community believed that this is where Jesus went in-between and the resurrected Jesus does not correct this view.
For my thought, Hades (as a place of the dead) and death are congruous terms used by John to convey the spirit-inhabited place and the physical reality of animation leaving the body.
In Revelation 1, death is mentioned three times. Jesus is described as "faithful witness, firstborn from the dead, and ruler of the kings of Earth" in verse 5. In John's vision, he falls before Jesus as if dead (verse 17) and is then "resurrected" before hearing the statement: “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."
Another interesting image in this statement is the use of "keys". What does this mean? In Revelation 3, John refers to Isaiah 22 and likens Jesus to Eliakim saying that with the keys, what he opens no one can shut and what he shuts no one can open. This is the same allusion in Jesus' words to Simon Peter in Matthew.
Within this imagery, keys represent authority.
To think about post-mortem Jesus, think in terms of the incarnation-- God is made present to the totality of human experience. We see this among the living in the gospels but it apparently also occurs among those who have gone beyond life.
Jesus, then, has not only experienced death (as an element of human existence) but has triumphed over it. This is demonstrated in resurrection and proclaims that Jesus did not simply pass through Hades, but emerges authoritatively and represents the new reality of life beyond Hades (check out the zombies in Matthew 27:52) and the control of death. "Firstborn from among the dead" becomes a title for Jesus here and among the early church (Colossians "firstborn over creation"), signifying that more will follow.
For this statement to be included in the beginning of Revelation sets the stage for the eschatological presentation of Jesus expressing the summation of the restoration of creation. This restoration encompasses all aspects of human existence: life and whatever place lays beyond. For communities facing persecution (like in Revelation) or a contemporary church facing death in the form of malaise, nihilism, and fear, Jesus has gone on before, experienced, and conquered. (Where is the place of death for you or your students?)
Our path is to trust in Jesus as leader as we follow after him in life and still in death. (How terrible to journey through that country with no guide!)