Early in the pandemic, the eight-man, Minneapolis-based vocal group's international following expanded exponentially via online musical missives that offered comfort to the sequestered and worried with calming harmonies. They eventually collected them on an album called "The COVID-19 Sessions."

For 2½ years, Cantus has been a model ensemble for making it through the pandemic, building its performances into schedules of isolation and frequent testing. No singer has ever had to miss a concert due to COVID — until Friday, when three of the group's four tenors were sidelined at the start of their busiest fortnight of the year.

Yet "Christmas with Cantus" is still slated for 10 performances at 10 Minnesota venues over the course of 12 days. This weekend, the group will be a sextet, as Cantus alum Zachary Colby has stepped into one of the tenor slots on a day's notice. The hope is that a full eight will be onstage for the Dec. 15-20 concerts.

So the harmonies were a bit thinner and the spirit more solemn at Friday's midday concert at Minneapolis' Westminster Hall. While there were some songs of celebration, more were rooted in reverence, a hue of melancholy creeping into the program. Which felt appropriate for an occasion that reminded all in attendance that we're not yet out of the woods this winter. The best option seemed to be sighing, putting your mask back on, and enjoying the music.

And there was much to enjoy. The program is constructed around the English "Lessons and Carols" tradition, with the lessons delivered by Twin Cities poet and spoken-word artist ShaVunda Brown. She proved to be the chief energy source at Friday's concert, her original works emphatically imploring listeners to embrace the inevitable changes we're experiencing.

In the concert's first half, the six singers offered four comforting, contemplative songs, starting with Joel Phillips' gentle lullaby-like setting of William Blake's "Little Lamb." Pop-folk artist Sara Bareilles' "A Soft Place to Land" proved wistfully touching, and B.E. Boykin's "O Magnum Mysterium" and Christopher H. Harris' arrangement of "Silent Night" equally involving.

But the group was performing in front of large shaded windows overlooking Nicollet Mall on a gloomy December day, so it seemed a particularly dimly lit performance, leaving me longing for something to brighten things. Despite a couple of upbeat numbers, a meditative mood continued to hold sway, thanks to a lovely piece by Adolphus Hailstork and Cantus' signature song, Franz Biebl's "Ave Maria."

Not until an encore of "Go Where I Send Thee" did a sense of celebration emerge that matched the energy of Brown's consistently life-affirming readings. While the singers deserve kudos for soldiering on, I hope that her spirit will rub off on them more with each concert.

"Christmas with Cantus"

When and where: 7:30 p.m. Saturday, Capri Theater, 2027 W. Broadway, Mpls.; 3 p.m. Sunday, Trinity Lutheran Church, 115 N. 4th St., Stillwater; 7:30 p.m. Monday, Fridley High School Auditorium, 6000 W. Moore Lake Dr. NE., Fridley; 11 a.m. Thursday, Meetinghouse Church, 6200 Colonial Way, Edina; 7:30 p.m. Dec. 16, Ordway Concert Hall, 345 Washington St., St. Paul; 7:30 p.m. Dec. 17, Zumbro Lutheran Church, 624 3rd Ave. SW., Rochester; 3 p.m. Dec. 18, Hamline Church, 1514 Englewood Av., St. Paul; 7:30 p.m. Dec. 19, Westonka Performing Arts Center, 5905 Sunnyfield Road E., Minnetrista; 7:30 p.m. Dec. 20, Chapel of St. Thomas Aquinas, N. Cleveland and Ashland avenues, St. Paul.

Tickets: $5-$40, available at 612-435-0055 or cantussings.org

Note: Saturday's concert will be available for streaming at cantussings.org through Jan. 4.

Rob Hubbard is a Twin Cities classical music writer. Reach him at wordhub@yahoo.com.