With no lead vocalist, Hartman and Hough shared singing duties on the self-titled debut, which was released in 1974. Featuring "tight, Allman Brothers-type dual guitar lines and riffs", "Petra" also featured the comical country tune "Lucas McGraw", which became something of a cult classic, and the seminal "Backslidin' Blues", the first contemporary Christian blues song put on vinyl. The rarity of being a Christian rock band led to larger concerts and greater popularity, and Myrrh asked Petra to record a second album aimed principally at non-Christians, reflecting the evangelistic nature of the band's shows.