But the Calvinistic Psalm took its authority and its appropriateness from its divine inspiration. It must be Holy Scripture, first of all; and then it became metrical merely to facilitate its congregational rendering. Calvin had determined to make the Psalter the praise book of the Reformed Church, and to that end never rested till the praise book was complete. The excellence of that praise book, both literary and musical, carried Metrical Psalmody through France by its own impulse; and the Genevan tunes spread Metrical Psalmody more widely through Europe. Calvin’s great authority made Geneva the center of the Reformed world, and the Genevan Psalmody became the inspiration and the model for the Reformed Churches in England and Scotland. In this process of extension the practice of singing metrical Psalms hardened into the rigidity of an established custom. The Calvinistic precedent became the Calvinistic principle; the metrical Psalm became the norm and rule of praise throughout the whole Reformed Church, to the virtual exclusion of all hymns of human composition.
—Louis Benson, John Calvin And The Psalmody Of The Reformed Churches (1907).