Tears, Idle Tears
divine despair
Not religious grief—'divine' means inexplicable, beyond rational cause. The tears have no object, no reason he can name.
from the underworld
Classical reference to the dead. Ships bringing friends back = resurrection fantasy. The metaphor is about memory retrieving the lost.
dark summer dawns
Oxymoron—summer dawns aren't dark. He's describing perception from a deathbed: the world growing dim while life goes on outside.
lips that are for others
Not the dead—the living who belong to someone else. Lost love and dead love are equally unreachable.
Death in Life
The paradox named: being alive but haunted by the past is a form of death. Memory kills the present moment.