The impact of faith and religion on the lives of various characters, which the Prologue immediately introduces, is the novel’s most important and overt theme. It’s initially framed through Bishop Latour’s experiences. Latour found God early, and his religiosity drove all his major life choices. A deeply devout man, he feels “called” to missionary work. He’s willing to endure great difficulty in order to spread God’s word even in the furthest reaches of the church’s territory, and he puts his own comfort aside during trying experiences. After he loses his way in the desert while traveling to his new diocese in Santa Fe, he keeps his thoughts on God and on his goals: “The Passion of Jesus became for him his only reality; the need of his own body was but a part of that conception” (13). He stops only to pray by a cross-shaped tree, and when he finishes his devotions, he resumes his journey. He carries this deep religiosity throughout his entire ecclesiastical career in Santa Fe and at the end of his life feels satisfied that he served both God and the Catholics whose souls God had entrusted to him in his role as bishop.

Latour’s friend and fellow priest Joseph Vaillant also experiences religion as a calling.