STATEMENT OF CLARIFICATION ON THE SOLEMNITY OF CHRISTMAS AND FULFILLING ONE’S MASS OBLIGATIONS FOR THE DIOCESE OF OAKLAND
This year, the Solemnity of the Nativity of the Lord (Christmas) falls on a Monday. The day before, Sunday, is the celebration of the Fourth Sunday of Advent. In order to reduce confusion and to bring some explanation, the following understanding of the Mass obligation is provided, and should in some form be disseminated to the faithful of the diocese.
Masses celebrated in the diocese for the Fourth Sunday of Advent should occur either as a lawful anticipated Mass on Saturday, December 23rd, or during the morning/day of Sunday, December 24th, using the Propers and Readings particular for the Fourth Sunday of Advent. Normally-scheduled Sunday “evening” Masses (for the Fourth Sunday of Advent) are not to be celebrated as such this year. Beginning on the evening (before or after First Vespers/Evening Prayer I) of Sunday, December 24th, and continuing throughout the day of Monday, December 25th, all Masses celebrated should be for the Nativity of the Lord, with the Propers and Readings particular for Christmas (At the Vigil, during the Night, at Dawn, during the Day).
For the Faithful and the obligation for attending Mass, it should be communicated that it is not lawful to fulfill multiple obligations from attending one single Mass. Therefore, going to Sunday Mass (either on Saturday evening or Sunday day) for the Fourth Sunday of Advent will not fulfill the holy day obligation for Christmas. Likewise, attending Sunday evening Mass (for the Vigil of Christmas) or Monday Christmas Mass will not fulfill the normal Sunday obligation for the Fourth Sunday of Advent. The faithful are therefore encouraged to attend one Mass for the Fourth Sunday of Advent and a second Mass for the Solemnity of Christmas.
Note that the law prescribes when certain Holy Days of Obligation (Jan 1, Aug 15, etc.) fall on a Monday, they are specifically mentioned and the Monday obligation is suspended for that year. Christmas is not ever mentioned as such, so the obligation remains, whether fulfilled on Christmas eve or Christmas day. That obligation would be separate from the normal Sunday obligation.
Accordingly, for this year the holy day obligation for the Solemnity of Mary, Mother of God, on January 1 is not binding because it will fall on Monday (see Canon 1246 §2 USCCB).
To summarize, the obligation to attend Mass remains for both the fourth Sunday of Advent (fulfilled by attending a Saturday evening anticipated Mass or a Sunday Morning/day Mass) and the Solemnity of Christmas ( fulfilled by attending either a Sunday evening Christmas Vigil mass or a Monday Christmas Mass). Also this year, the Solemnity of Mary, Mother of God, falls on a Monday (Jan 1). However, since this is a holy day of obligation that can be abrogated if it falls on a Monday, the obligation is not in effect.