The guitar great teamed up with the Dean of Birmingham, the Very Reverend Catherine Ogle, on the arrangement, inspired by Psalm 133, which features Birmingham Cathedral Choir.
The track is called How Good It Is.
"It's great to be involved with the Cathedral and doing something for it," he said. "When Catherine mentioned it, it felt like a nice thing to do, to be able to give something to the city.
"We've done instrumental work before with orchestras and it's something I enjoy doing. It's completely different from any of the heavier stuff. This is a completely new piece of music and I'm really pleased with it."
Iommi will return to Birmingham in February (17) to play Black Sabbath's last-ever gig.
Dean Ogle, who will soon leave Birmingham to become Dean at Winchester Cathedral in England, was thrilled to work with Iommi, whose music has often been linked to the devil, because it was a sign he was on the mend after his battle with cancer.
"When Tony was unwell, we got to know one another better when I began to pray for him and kept in touch with Tony and his wife about his health," she explained. "This is a most wonderful gift Tony offered to the Cathedral. He has a huge fan base in the city.
"The words come from scripture and are really positive about people living together in peace and harmony. This is what Birmingham is all about... It's wonderful when a son of this city, who has had tremendous success, wants to give something back. That he wanted to do that through the Cathedral is very touching."