It must be "soul food". There's material world "below" and there's world of ideas "above". Matter has essence, so it's substantial; and ideas must be "supersubstancial". That "lord's prayer" tells something along this line: "oh, the god who lives above, your name is sacred, your material world reflects your ideas above, give us soul food, save us from duality, ..." (my own interpretation, sounds a bit egyptian).