Question: When a holy day of obligation has different readings and Gospel for the vigil Mass and Mass of the day of celebration in the ordo, can a priest change the order of the readings? For instance, if the Gospel for the actual holy day is more applicable to the feast, can it be used in place of the Gospel for the vigil?
— Bob Pyznar, via email
Answer: It depends. For memorials of the saints, priests can use the readings of the day or readings for the saint or observance. Even in lesser feasts, there may be an indication that the “gospel (or reading) is proper for this day.” This means that a priest should use the proposed Gospel even in a lesser feast since something in the assigned Gospel is especially pertinent to that day. This is especially true of biblical saints. Generally, however, for a simple memorial of a saint, the priest has options for the readings.
For higher ranking feasts and especially for solemnities, the priest is more bound to use the appointed readings for the feast day. The list of readings and other rules of the calendar day are found in a book called the “Ordo.” This describes the rules and options for each day, what, if any saint, is being commemorated, and the prayers and readings that are either required or optional for that day. It also instructs on the color of vestments and other particulars, such as whether the creed or Gloria are to be said. A priest is free to choose from options if they are present, but he ought not depart from the alternatives set forth in the ordo except for a serious pastoral reason.
