To hear the Boys Choir of Harlem is to hear the sound of faith, hope and love. Strong words for a group of 40 boys who, if they weren’t singing with Dr. Walter Turnbull, might be out on the streets facing the degradation of inner- city kids in America these days.

But hear them sing “It Don’t Mean a Thing (If It Ain’t Got That Swing)” or the spiritual “Every Time I Feel the Spirit” or Shubert’s Mass in G, and you can’t help but be a believer.

Indeed, everyone was a believer when the Boys Choir performed Saturday to an overflowing and enraptured audience at the Maine Center for the Arts in Orono. The boy singers, who were here last winter, won over the hearts of Mainers once again. Whether delivering the angelic strains of a Bach cantata or the hip-hop funk of “Power” (a Boys Choir standard about having the power to be the best you can be), these young men showed just how amazing grace can be.

Unquestionably, these kids — and the older alumni who travel with them to round out harmonies — have worked hard to become so sophisticated — and some of them so young and tiny they look as if a swift wind could carry them skyward. When they sing, it’s glorious. When they dance, it’s sharp. (In an interview last week, Turnbull said the boys love the singing, but what they REALLY care about is that the girls get to see them dance! And, lordy, dance they did.)

In short, the boys’ orchestration of this event is always exacting, professional, shipshape, well-mannered and confident. All of this is to the credit of Turnbull. His focus is primarily the music, and, as one admirer said to him after the show, “Honey, the Lord put the music in you.” Through the music, he reaches the child and takes him to a better world that has to do with self-respect, focus and that all-too-rare phenonmenon of living up to one’s potential. Last year, the Choir Academy, a fourth-through-12th-grade school which has an enrollment of more than 500 children, both boys and girls, graduated 16 students. Each one was accepted into college. Those are numbers that, rightfully, make Turnbull proud.

In addition to 45 minutes of church music, including a Benedictus with melting harmony by 12-year-old soprano Krstyn Daney, tenor Michael McDonald and baritone Daniel Billings, the audience was treated to a program of show tunes, jazz hits and contemporary music. The boys heartily entertained with both music and clever, humorous choreography. A big-time attitude marked every move they made, and attitude is what it’s all about, after all. If a boy, while singing Bach, reaches down to pull up his socks or reaches up to wipe his nose, it’s all part of a beautiful combination of angel and real child.

Probably the most poignant piece of the night was “We Are Heroes,” a song with beats reminiscent of music by the 1970s group The Temptations. The chorus of the song goes, “All black boys are born of heroes.” These boys — born surrogately of Turnbull, his miraculous vision and his call to action — are heroic. Their work has that perfect combination of serious discipline and personal freedom. That alone is a powerful step toward creating fully realized human beings — who also know how to have fun and can sing like champs.