Gregory Xavier Volz is a Christian

Christian

A Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth as recorded in the Canonical gospels and the letters of the New Testament...

 singer. He is most noted for being the former lead singer of Christian rock band Petra

Petra (band)

Petra is a music group regarded as a pioneer of the Christian rock and contemporary Christian music genres. Formed in 1972, the band took its name from the Greek word for "rock"...

 from 1979 to 1985 and is currently the lead vocalist of the reunited lineup.
Volz showed great skills in singing from a very early age. Being a self-taught musician, when he was 13 years old, he started his own band called The Wombats. As he grew up, he went on to share the stage with the likes of Janis Joplin

Janis Joplin

Janis Lyn Joplin was an American singer, songwriter, painter, dancer and music arranger. She rose to prominence in the late 1960s as the lead singer of Big Brother and the Holding Company and later as a solo artist with her backing groups, The Kozmic Blues Band and The Full Tilt Boogie Band...

, Chicago

Chicago (band)

Chicago is an American rock band formed in 1967 in Chicago, Illinois. The self-described "rock and roll band with horns" began as a politically charged, sometimes experimental, rock band and later moved to a predominantly softer sound, becoming famous for producing a number of hit ballads. They had...

 and others.