“Regulation of the sacred liturgy depends solely on the authority of the Church, that is, on the Apostolic See and, as laws may determine, on the bishop. Therefore no other person, even if he be a priest, may add, remove, or change anything in the liturgy on his own authority” (Constitution on the Sacred Liturgy, 22, repeated in documents like Sacram Liturgiam; Tres Abhinc Annos; CIC 841, 846; and many other laws and regulations). Deviations from the Order are illicit, and when done intentionally they’re a grave offense both against the Church and the faithful who have a right to an authentic liturgy (Inaestimabile Donum, CSDW, April 3, 1980).