I feel compelled to respond to this, as I’d like to make a suggestion. We need to be very careful to not take an overly legalistic approach to anything. The “letter of the law,” is exactly as so many have outlined. One is to assist at Mass on the Solemnity. Which rite the liturgy is celebrated in, or even if it is the liturgy of the actual solemnity, matters not in whether one meets one’s obligation.
But, we don’t merely have an obligation to attend Mass. God calls us to an ever deeper, more vibrant, spiritual life. As Catholics, we think with the mind of the Church and follow the liturgy as the Church instructs us. So, while, yes, one could attend Mass both Sunday morning and Sunday evening, and meet the letter of the law, personally, I would argue that this individual is not meeting the spirit of the law. The spirit of the law is to celebrate the Immaculate Conception. Assisting twice at the Mass for the Second Sunday of Advent deprives the person of fully entering into the mystery that is the Immaculate Conception.
Are there good reasons for doing this, however? Certainly. Perhaps someone knows that he/she must travel all day today and it is either go to Mass for 2 Advent twice, or commit grave sin. By all means, take the option of not committing grave sin. However, this doesn’t change the fact that the ideal is to assist at both celebrations.
To draw a comparison, popular youth speaker Chris Stefanick has a popular YouTube video out, where he tells a story of a young man playing a video game during Mass, the entire time. Did that young man meet his obligation to attend Mass? I suppose technically he did. But, did he enter into the liturgy? Did he celebrate the liturgy as the Church intends and desires? Hardly.
If the readings really “don’t matter,” as we are quick to be reminded, why did the Church go to great length to give us the three year cycle of Scripture readings? Why were specific readings meticulously chosen for specific feasts? My fear is that this debate, which happens pretty much every time IC falls on a Saturday or Monday, far from leading the faithful to a deeper appreciation of the liturgy, leads them to treat it with a certain banality that all that really matters is “meeting my obligation,” punching my timecard so to speak. Remember, “the sabbath was not made for man, but man for the sabbath.” Celebrate both feasts. It’s what Holy Mother Church desires, even if it’s not the technical “letter” of the law.
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