So.. some rough thoughts on why we dream.
If sleep = death
and waking up = resurrection
Then what of those people who die now, but Christ has yet to return? Where do they go?
Like Jesus on the cross says... this day you will be with me in paradise.
But is paradise the finished new creation, new kingdom, new temple Jerusalem?
Dreams are fragments and mostly incoherent.. but they could be reflective of that pre new-creation paradise; or, it could be reflective of that pre new-creation Sheol.
So just as we have nightmares, which represent the deep where the non-Christians are thrown into before they are resurrected just to die a second death; so also we have joyous dreams which represent the paradise where His sons and daughters go to before being resurrected to experience a new, physical and more real new creation paradise. dreams are but the in-between... before the new kingdom is created.