Gregorian chants are mostly based on Old Testament texts, predominantly from the Psalms. Decisive for their interpretation in the light of the New Testament are texts of the Church Fathers (Augustine, Gregory the Great, etc.). The texts often do not follow their canonical order in the Bible, but were primarily compiled on the basis of broader associations. Hence, it is not uncommon for new content references to emerge that are committed to a Christian perspective, emotionally and theologically very bold. This article describes an imaginary ‘Gregorian Composition Workshop’: the individual ‘chambers’ include compiling texts, the choice of a suitable mode and melody, as well as the most refined rhythmic differentiations. The final piece, through its unique quality as the ‘sounding word of Holy Scripture’ permits an intensive view of the spirituality of the ninth and tenth centuries, and a realistic understanding of the Psalms as the basis of Christian existence.