Immaculate Conception
of Mary

December 8

The Catechism of the Catholic Church explains holy days of obligation this way:

On Sundays and other holy days of obligation, the faithful are to refrain from engaging in work or activities that hinder the worship owed to God, the joy proper to the Lord's Day, the performance of the works of mercy, and the appropriate relaxation of mind and body.

Family needs or important social service can legitimately excuse from the obligation of Sunday rest.

The faithful should see to it that legitimate excuses do not lead to habits prejudicial to religion, family life, and health [CCC 2185].

The Code of Canon Law spells out when the holy days of obligation are on the Church’s universal calendar:

Can.  1246 §1. Sunday, on which by apostolic tradition the paschal mystery is celebrated, must be observed in the universal Church as the primordial holy day of obligation. The holy days of obligation in the United States are as follows:

• Mary, Mother of God (always celebrated January 1, but if this occurs on a Saturday or a Monday there is no obligation to go to Mass)
• Epiphany (this has been permanently translated to the first Sunday after January 1)
• Ascension (this is celebrated on different days depending on which ecclesiastical province you live in; a few provinces celebrate it on the traditional date, which is the Thursday of the sixth week of Easter, but most provinces in the U.S. have transferred it to the seventh Sunday of Easter.)
• The Body and Blood of Christ (this has been permanently translated to the second Sunday after Pentecost)
• Assumption of Mary (always celebrated August 15, but if this occurs on a Saturday or a Monday there is no obligation to go to Mass)
• All Saints (always celebrated November 1, but if this occurs on a Saturday or a Monday there is no obligation to go to Mass)
• Immaculate Conception of Mary (always celebrated December 8)
• Christmas (always celebrated December 25)