This is what Justin Vernon said in an interview about this song:
"Perth" is this awakening or this birth. And to relate it to some of the conversation we've been having, it's sort of that moment when you have decided to wake up and take control. And "Beth/Rest" is the death, but it's a good death. It's good winter. But it's a rest; it's not this final thing. "Beth" seems like this really cool name for a place you just go to be in paradise forever."
This is what Justin Vernon said in an interview about this song: "Perth" is this awakening or this birth. And to relate it to some of the conversation we've been having, it's sort of that moment when you have decided to wake up and take control. And "Beth/Rest" is the death, but it's a good death. It's good winter. But it's a rest; it's not this final thing. "Beth" seems like this really cool name for a place you just go to be in paradise forever."
http://www.npr.org/blogs/allsongs/2011/06/23/137328981/bon-ivers-justin-vernon-talks-about-his-bands-new-album