Black Sabbath will be playing that song, presumably for the last time at Madison Square Garden, tonight. I had the thrill of seeing them earlier in the week. As I’ve written in the past, I’m only a recent convert, but I can’t stop listening to them.

The Thursday show started with their song “Black Sabbath,” the plodding art rock number that begins, “What is this that stands before me?” Ozzy Osbourne spreading his arms to indicate what or who he means: You the audience. It was clear right away what we were in for: a faux Satanic sacrament with the band as priests and us the audience as congregants.

I couldn’t stomach this theatricality about them when I first heard their music. Was it my Catholicism? I don’t think so. I could handle apostasy, but Satanism? Why?! It felt like WWF wrestling. I was also just young enough to catch them at the very end of their 1970s arc, when their sound had become full-on heavy metal. The kids with tranquilizers in the pockets of their army jackets listened to that kind of music. It sounded too damn noisy to someone who could spend hours throwing a frisbee around with the Allman Brothers on the tape deck.

When my wife, who did love their music as a teenager, came home one day with their greatest hits during the waning days of CDs, we’d listen to it while playing backgammon, and she’d point out every time the music changed keys in inventive ways. (My knowledge of actual music is limited by my tone deafness – and my sense of rhythm ain’t so good either.) I found their first few albums on vinyl and was mesmerized. After the lifetime of punk, metal, and speed metal that followed them –  all of which Sabbath arguably invented and handed off to others – their early stuff sounds downright tuneful. Operatic, and much more prog rock than I imagined.

I was a bit surprised this week to see Ozzy take it upon himself to lead us in clapping and shouting, and to chide us, “I can’t fucking hear you!” Partly he was being a good Satanic priest, but partly he’s just a singer in a rock band; if he’d fallen in with different blokes in ’68, he’d be singing about sex, like Foghat. If you watch the full show the clip above is taken from, days before Christmas in 1970, you’ll see that young Ozzy did a whole lot of this too, and it sinks in: These really are just some working class dudes from Birmingham who invented their own form of theater that’s part blues, part football stadium, and part apocalyptic morality.

It feels all the more real and urgent today when you notice the hunch in Ozzy’s shoulders: Clapping his hands over his head could be a physical therapy assignment. Guitarist Tony Iommi got treated for cancer recently (successfully, he says), but you can see from their age that these guys aren’t rebels. They’re not young Martin Luthers pounding grievances on a door, they’re the high priests in their own church, or at least the stars of their own pageant, whose conceit is that they’re high priests, and we’re members of the flock.

“War Pigs” wasn’t an abstraction to people who were living with the draft in 1970. It starts, “Generals gathered in their masses,/just like witches at black masses.” I know, he rhymes “masses” with “masses.” Lazy, but stick around! Crosby, Stills, Nash and Young were singing “Find the Cost of Freedom”; these guys were comparing Robert McNamara to a Satanic priest. The record version of the song ends with the verse:

“Now in darkness, world stops turning,
ashes where the bodies burning.
No more war pigs have the power,
hand of god has struck the hour.
Day of judgement, god is calling,
on their knees the war pigs crawling.”

Something I noticed in my years working with schizophrenics: Most paranoid schizophrenics a. love Black Sabbath, and b. also have a dose of grandiosity. If you believe there’s a conspiracy afoot to ruin your life, and the CIA and Martians and the staff at Kmart are all in on it, then you also will likely believe that you are a superhero, so at least it’s a fair fight.

It’s no wonder kids in Christian small towns keep dabbling in Satanism. He’s a presence in their cosmos already. Iommi and lyricist Geezer Butler put a Revelations kind of redemption into this particular song: You’re invited to partake of a titillating amount of the Satanic eucharist, but in the end we’re going to fall in line. In the video you’ll notice Ozzy merely hints at this redemption, finishing with an alternate set of lyrics, including this irresistible couplet: “It’s a place for all bad sinners/ Watch them eating dead rats’  innards.”

The spectacle itself is all the Satanism you need. I got the feeling on Thursday that I’d gone to an old chthonic rite of a dying cult: Before it was Black Sabbath, the band called itself “Earth.” Madison Square Garden, even though you go up to go inside, feels underground. The American and Canadian flags flew overhead – for hockey, I assume, though I’d love to see a Mexican flag there too – and it felt like a portal into the hell inside the North American soul.

In Houston that night the Republicans were imploding, but no one mentioned politics in the Garden. At the end of the show I got separated from my friends and texted, “I’m the white guy in a black coat.” 80% of us were white guys in black coats! I’m squarely middle-aged, but I’m sure I was below the median age there, and yet it felt like the conscience of North America: people who could stare into our own collective, murderous soul and still see some good. Humbled, and hobbled, like the guy carrying sticks on his back on the Led Zeppelin IV cover, we went down the escalators – or was it up?- to the train.