Lyric discussion by King of Some Island 

Cover art for My Boy Builds Coffins lyrics by Florence + the Machine

The song is about death being the great equalizer. Everyones going to die and then we shall all be in a coffin made by the same guy. Kings, queens, thieves, and beggars and even the coffin builder himself shall all end up in the same coffin in the same hole. We spend our whole lives trying to seperate ourselves and trying to put ourselves above others but in the end we all end up the very same. And the coffin builder knows this and thats why he only builds coffins, because he knows thats the only thing that he can give to everyone no matter who they are.

My Interpretation

100% agreed. This is also how I saw it.