Tonight at St. Mark’s Episcopal Church, pianist Mika Inouye teams with cellist Sandy Kiefer for a program ranging from two Bach cello preludes to Bruch’s moving “Kol Nidrei” (All Vows).

Mindful that today is Yom Kippur, Kiefer said in an interview last week, the Day of Atonement is the holiest day in the Jewish calendar, a time set aside for communal and personal atonement for sins committed in the previous year. Tonight, Kiefer said, is exactly Yom Kippur, so it’s all the more appropriate to play Bruch’s arrangement of the ancient Hebrew prayer. “It’s a very pleading, self-reflective piece.”

Inouye will play Chopin’s Waltz in C-sharp minor and Rachmaninoff’s “Etude Tableaux in G minor.” After one work by contemporary composer Arvo Pärt, the duo will conclude with Mendelssohn’s Sonata in D Major.

“Total happiness and energy,” Kiefer said, “with one very Kol Nidre-sounding middle movement.”

Saturday afternoon, Quadrivium, a relatively new professional vocal ensemble based in Durango, will offer an Interfaith Choral Workshop at First United Methodist Church. It will be capped by a formal recital at 5 p.m. Sunday.

Organized in 2016, Quadrivium consists of soprano Charissa Chiaravalloti, mezzo-soprano Kerry Ginger, tenor Erik Gustafson, and guest bass-baritone Toby Vaughn Kidd.

Now in its second year as a performing entity, Quadrivium came up with the idea of a weekend workshop and formal recital.

“There are so many invested singers in the area who share a church choir tradition,” Ginger said in an interview last week. “So, we’re offering an opportunity to learn more about vocal technique.”

The afternoon will be divided into technical sections structured around a nondenominational hymn by Ola Gjello with a Latin text: ‘The Ground.”

By 3 p.m., the singers will come together again under guest conductor Thomas Heuser, music director of the San Juan Symphony, with strings and piano, all singing the Gjello hymn.

Quadrivium’s Sunday recital is titled “Hosanna!”

“It’s a concert celebrating the power of the heavenly spirit,” Ginger said.

Works by William Byrd, Barber and others will be included, ending with Quadrivium singing “The Ground.”

“The term ‘Quadrivium’ refers to the ancient Greek-cum-medieval idea of a well-rounded liberal arts education,” Ginger said. “But it also signifies an intersection or coming together. We are so excited to offer community singers a forum to do just that because our mission is to perform fine small-ensemble vocal music to enrich our own community.”

Judith Reynolds is an arts journalist and member of the American Theater Critics Association.