The Holy See has clarified that the Solemnity of the Immaculate Conception remains a holy day of obligation this year.
While the feast, celebrated annually on Dec. 8, has always been a holy day of obligation, this year the feast is transferred to Monday, Dec. 9. This is because Dec. 8 is the Second Sunday of Advent.
Some holy days of obligation that fall on a Sunday are often celebrated either on the preceding Saturday or the following Monday, which is the case this year for the Immaculate Conception. The Solemnity of the Immaculate Conception is a holy day because it is the patronal feast of the United States of America. Not all holy days of obligation (for example, Christmas) are moved.
A holy day of obligation means that Catholics are obliged to attend Mass in honor of the particular feast. Thus, this year, Catholics are to worship God at Mass both on Sunday, Dec. 8 and Monday, Dec. 9, the transferred date for the Immaculate Conception.
If it is impossible to attend Mass, such as in the case of illness or needing to care for infants, the obligation ceases because no one is bound to do the impossible. Catholics, on an individual basis, may also be dispensed from the obligation to attend Mass by their own pastor for each particular feast or Sunday on account of necessity or a just cause.
“Whenever January 1, the solemnity of Mary, Mother of God, or August 15, the solemnity of the Assumption, or November 1, the solemnity of All Saints, falls on a Saturday or on a Monday, the precept to attend Mass is abrogated,” according to the United States Conference of Catholic Bishops.