Musicae Sacrae §30

³⁰ These laws and standards for religious art apply in a stricter and holier way to sacred music because sacred music enters more intimately into divine worship than many other liberal arts, such as architecture, painting and sculpture. These last serve to prepare a worthy setting for the sacred ceremonies. Sacred music, however, has an important place in the actual performance of the sacred ceremonies and rites themselves. Hence the Church must take the greatest care to prevent whatever might be unbecoming to sacred worship or anything that might distract the faithful in attendance from lifting their minds up to God from entering into sacred music, which is the servant, as it were, of the sacred liturgy.