Olivier Messiaen was a prominent twentieth-century French composer. His musical language includes highly complicated concepts derived from a variety of sources. Hindu rhythms, Greek rhythms, and bird calls influenced him deeply; his Catholic faith, however, had the greatest impact on his compositions. I provide a detailed analysis of two religiously motivated pieces from his Vingt Regards sur l'Enfant-Jesus (Twenty Gazes upon the Infant Jesus), one of the most remarkable solo piano works of the twentieth-century, to explore how he integrates the Christian theology into his musical language. Je dors, mais mon c