This December, the Feast of the Immaculate Conception of Mary is on Monday, Dec 9. In the Diocese of Sioux City, it is still a Day of Obligation. The Catechism of the Catholic Church explains,

"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 Church recognizes genuine needs arise that might interfere with our worship of God on these days (i.e. attending Mass), such as an inflexible work schedule or taking care of a seriously ill family member. However, mere inconvenience does not excuse us.

The graphic illustrates how we can fulfill our two obligations. Please note that Mass on Sunday evening could fulfill either your Sunday obligation (if you haven't attended Sunday Mass yet) or Immaculate Conception obligation (if you went to an earlier Sunday Mass) but not both.