Solo vocalists across evangelical Christianity use their performance practices to communicate both the truthfulness of words they sing and their personal beliefs that the words are true. Beyond this, in many evangelical circles, vocalists also seek to convey personal authenticity as they sing in worship services, in the Rousseauian sense of being spontaneous and emotionally self-expressive. But, some evangelical vocalists reject performative authenticity on grounds of sensuality and worldliness, as revealed in my fieldwork with self-identified fundamentalists in churches loosely connected with Bob Jones University (Greenville, South Carolina, USA). On a deeper theological level, their beliefs about salvation, sanctification, and corporate worship also motivate their performance choices. The microcosm of fundamentalists' vocal practices reveals a broader tendency in evangelicalism: the louder arguments about popular musical styles often rely on a sacred-profane model, but underlying motivations reflect differing understandings of personal truthfulness and worship.