Lyric discussion by msnovember 

Cover art for Demons lyrics by National, The

I'm pretty certain that it's "paint the blood." I think you're spot on, tori, with the palms being a reference to people hanging the palms from Palm Sunday, but I think the "paint the blood" is a biblical reference as well (or at least that's how I took it the first time I heard the song). I assumed it was a reference to the story in Exodus in which God instructs the Israelites to paint their doorposts with the blood of the lamb to let him know which houses to pass over when he unleashes his latest plague (the one in which the first born son of every household will die). Those who painted their doorposts would be safe from this plague. I'm not particularly religious, but this is the basic story as I remember it from my study of the Bible. The line "paint the blood and hang the palms on the door" seems to me to be a reference to the idea of having some sort of charm/protective sacrament that will keep trouble away from the narrator. I know that some cultures view the hanging palms as a way to ward off evil spirits, which ties in pretty neatly with the title of the song.

My Interpretation