I’m trying to explain this to a friend of mine. He understands the need to go on Sundays, but why for the feast of the Immaculate Conception tomorrow? Why specifically do we go on these days and assert that this is a necessity?
Catechism**2042 **The first precept (“You shall attend Mass on Sundays and holy days of obligation and rest from servile labor”) requires the faithful to sanctify the day commemorating the Resurrection of the Lord as well as the principal liturgical feasts honoring the Mysteries of the Lord, the Blessed Virgin Mary, and the saints; in the first place, by participating in the Eucharistic celebration, in which the Christian community is gathered, and by resting from those works and activities which could impede such a sanctification of these days. Latin Canon Law lists
ten such days, in addition to all Sundays, however, they may be transferred or suppressed;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 following days must also be observed:
- the Nativity of our Lord Jesus Christ,
- the Epiphany,
- the Ascension,
- the Body and Blood of Christ,
- Holy Mary the Mother of God,
- her Immaculate Conception,
- her Assumption,
- Saint Joseph,
- Saint Peter and Saint Paul the Apostles,
- and All Saints.
§2. With the prior approval of the Apostolic See, however, the conference of bishops can suppress some of the holy days of obligation or transfer them to a Sunday.
For eastern Catholic Churches, they each have their own particular law, but in general the easten canon law CCEO shows in common, five beyond Sundays:Can. 880 3. Holy days of obligation common to all the Eastern Churches, beyond Sundays, are
- the Nativity of our Lord Jesus Christ,
- the Epiphany [Theophany],
- the Ascension,
- the Dormition of the Holy Mary Mother of God
- and the Holy Apostles Peter and Paul
except for the particular law of a Church suiiuris approved by the Apostolic See which suppresses a holy days of obligation or transfers them to a Sunday.