One hour. Nearly two dozen songs. Four members — two more than they had a year ago. On Sunday night the Thermals played a sold-out show at Bowery Ballroom. They scrambled through a set that included cryptic prayers, mutated political slogans and unfinished love stories, but they never strayed far from their bare-bones formula: a few chords, a few minutes and the song was done.

The night began with “Here’s Your Future,” the first song from the most recent Thermals album, “The Body, the Blood, the Machine” (Sub Pop). Like most of the songs on the album, this one is about an exodus, and it reduces the sixth chapter of Genesis to one characteristically pithy couplet: “God said, ‘Here’s your future/It’s gonna rain.’ ”

The Thermals evolved out of a gentle indie-rock band from Portland, Ore., called Hutch and Kathy. Kathy Foster, a bassist, and Hutch Harris, a singer and guitarist, recruited a drummer and recorded a loud demo tape that became the Thermals’ debut album, “More Parts per Million.” After an exuberant 2004 follow-up with an exuberantly unprintable title, they lost their drummer but kept going; Ms. Foster does double duty as a drummer on "The Body, the Blood, the Machine."

The old exuberance remains, but the most recent CD is also vivid and obsessive; faith and fatalism echo through every song. At times it sounds like a faster and cheaper companion to “Separation Sunday,” the religion-obsessed 2005 album by the Hold Steady. (As it happens, the two bands are well acquainted, and at least one member of the Hold Steady was in the crowd.) Even more than that band, this one thrives on the tension between straight-ahead music and twisty lyrics. One of Sunday’s highlights was “Returning to the Fold,” a perfectly ambivalent song about belief and belonging — the lyric booklet transcribes one line as, “i forgot i needed god like (a) big brother” — that’s built on a loud, rude guitar riff.

After the album was finished, Ms. Foster and Mr. Harris recruited a drummer, Lorin Coleman, and a second guitarist, Joel Burrows, whose chords sometimes allowed Mr. Harris to ignore his guitar and gesticulate. And Ms. Foster kept kicking the songs forward; in the venerable punk tradition she played almost nothing but rapid-fire down-strokes.

There are a few places where “The Body” starts to drag, and although the Thermals never tired on Sunday night, it was sometimes hard to keep up with their relentless pace. But at a Thermals concert if one song leaves you cold, you can always wait a minute or so for the next one. And the best new songs — like the (very) minor hit “A Pillar of Salt,” which could be about escaping to America, or from it — showed just how much joy and mystery can still be wrung from a few well-chosen chord changes. “I stick to the ground,” Mr. Harris yelped, turning a refugee’s tactic into a punk-rock strategy.