Chautauquans are in for some surprises at this Sunday’s Sacred Song Service that even Jared Jacobsen, organist and coordinator of worship and sacred music, is unaware of.

The weekly hymn service will be accompanied by the Voices of Trinity, a group whose 85 members are always incorporating new ideas into their music.

“What I can guarantee is that they will get the whole Amphitheater clapping and cheering for them before it’s over,” Jacobsen said.

At 8:15 p.m. Sunday in the Amphitheater, Jacobsen will perform this week’s Sacred Song Service with guest choir Voices of Trinity. The choir is from Trinity United Church of Christ in Chicago, the same church at which this week’s pastor, the Rev. Otis Moss III, serves as senior pastor.

Jacobsen said when Moss comes to Chautauqua Institution “it’s kind of a package,” typically including both Moss and a group of singers from his congregation.

“For me it’s sort of a mystical experience [when Moss preaches], because it’s as though the Holy Spirit is coming down through him and coming out through his preaching,” Jacobsen said. “He’s an incredibly bright man and he’s incredibly grounded in how to preach. … He is a master at that, but the magic of Otis in the pulpit is something that has to be experienced.”

Jacobsen said Chautauqua always tries to bring the best people from the field of music.

“This is very much in line with Chautauqua’s feeling about the wide spectrum of music from the very beginning of Chautauqua in 1874,” Jacobsen said. “It always was a sense that if it was any kind of music, a way of making music or a way of performing music or a style of writing music, that we felt people needed to know about here at Chautauqua, we brought them here to be in residence.”

Many of the choir members have day jobs, and Jacobsen said it’s a big deal that they are traveling all the way to Chautauqua. Some singers will walk off the stage and immediately go catch an overnight train to make it back to Chicago for work the next morning.

Jacobsen said by nature, Voices of Trinity performances are always very “freewheeling” and unexpected — sometimes they even bring dancers.

“I’ve learned that I need to be open to the surprise because even if I’m pretty sure what is coming, I’m never really sure until it goes by — and I love that, I just love that,” Jacobsen said. “And that is such an essence of Chautauqua: that we are open to the adventure of all kinds, whether it’s visual arts or acoustical art, whether it’s sacred music or secular music, Chautauqua is all about opening people up to the adventure.”