The most important day is a Holy Day of Obligation, you are required to attend Mass on that day. If you dont attend, it will count as a mortal sin. Here is a list of Holy Days:
January 1, the solemnity of Mary, Mother of God;
Thursday of the Sixth Week of Easter, the solemnity of the Ascension;
August 15, the solemnity of the Assumption of the Blessed Virgin Mary;
November 1, the solemnity of All Saints;
December 8, the solemnity of the Immaculate Conception;
December 25, the solemnity of the Nativity of Our Lord Jesus Christ.
Also, everyone Sunday you are required to attend Mass.
Here’s what the Code of Canon Law says about Holy Days:
*Canon 1247
On Sundays and other holy days of obligation the faithful are bound to participate in the Mass; they are also to abstain from those labors and business concerns which impede the worship to be rendered to God, the joy which is proper to the Lord’s Day, or the proper relaxation of mind and body.
Canon 1248
- The precept of participating in the Mass is satisfied by assistance at a Mass which is celebrated anywhere in a Catholic rite either on the holy day or on the evening of the preceding day.
- If because of lack of a sacred minister or for other grave cause participation in the celebration of the Eucharist is impossible, it is specially recommended that the faithful take part in the liturgy of the word if it is celebrated in the parish church or in another sacred place according to the prescriptions of the diocesan bishop, or engage in prayer for an appropriate amount of time personally or in a family or, as occasion offers, in groups of families. *
The next important day is a Solemnity, it is not as important as a Holy Day of Obligation and you are not required to go to Mass on a Solemnity. There are several Solemnities throughout the Church Year.
The next important day is called a Feast Day or sometimes called a Memorial Day. It is a special dayset aside in the Church Year to remember important people such as saints and events through the course of the Catholic faith from the time of Mary’s birth all the way through today. The calendar of saints has been changed throughout Church history to remove saints so that others may be celebrated also. There are many feast days throughout the Church Liturgical Year. Almost every day of the month has a special saint of the day. For a list of all Solemnities, Feast Days & Memorial Days go to this website:
cwo.com/~pentrack/catholic/romcal.html
Also, the final day is called a Feria (Latin for “free day”). A Feria is a day of the Liturgical Year on which there are no set Saints to honor.
God Bless! +