Here are some helpful articles on these topics:
Sabbath and Sunday
From Sabbath to Sunday: How the Church Moved Its Holy Day (James P. Guzek, This Rock, February 1999)
Did the Catholic Church "Change the Sabbath"? (Jimmy Akin, National Catholic Register, 11 October 2012)
The Catholic Encyclopedia: "Sunday"
The Catholic Encyclopedia: "Sabbath"
The Catholic Encyclopedia: "Sabbatarianism, Sabbatarians"
Sabbath or Sunday: What Does Holy Scripture Say? (Bob Stanley)
On Keeping the Lord's Day Holy (Dies Domini): Apostolic Letter of Pope John Paul II (31 May 1998)
Sunday vs. The Sabbath (Dr. Tim Gray, 12 March 2012; Catholic Answers Live, audio)
Sabbath or Sunday? (Church fathers)
Did Jesus alter the commandment about observing the sabbath? (Catholic Answers: "Quick Questions")
Did the early Church move the Sabbath from Saturday to Sunday? (Peggy Frye)
What about the Seventh-day Adventist claim that the sabbath shouldn't have been changed to Sunday? (Michelle Arnold)
The Sabbath or the Lord's Day (Catholic News Agency)
How Should We Keep the Sabbath? (Fr. William Saunders, Arlington Catholic Herald, 25 May 1995)
Sunday Obligation to Attend Mass
Why Is It a Mortal sin to Miss Mass? (Fr. Ray Ryland, This Rock, July 2000)
Forget Mass? Not a Mortal Sin (Karl Keating, This Rock, Nov. 2003)
FAQ About Sunday Obligation: Not Going to Mass (Catholic Doors Ministries)
Sunday Obligation, Jimmy Akin
Fulfilling the Sunday Obligation on Saturday (+ Part Two), Jimmy Akin
See also The Catechism of the Catholic Church: #2168-2195.
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The following remarks of mine were due to the comments of a Protestant seriously considering Catholicism. First I had written:
Like many Catholic things, this is widely misunderstood as yet another legalistic burden, whereas Church attendance ought to be seen as a privilege and joy, and as an extension of the OT Sabbath principle.This person took issue with my characterization and stated that legalism was indeed a serious problem to address and that "there is a difference between doing something because we are told and doing something because it's a response of love " and "my response to the Mass is first an act of love and faith. If it's simply an obligation, then my heart has not found it's hope. It is a ritual with no meaning other than a symbol." I replied in turn:
I think it's one of those things that Protestants object to that show they have too much time on their hands, along with. e.g., crucifixes: "those goofy Catholics are meditating on Jesus dying for us???!!! We can't have that!" Carping on and on about compulsory church attendance seems to me to be another huge non-issue.
I agree with virtually all of what you wrote.
The thing I would note in this regard is that not all Christians, by a long shot, are motivated out of sheer love for the Lord and desire to please Him and to lead a saintly life. In fact, I would argue that this lamentable deficiency is true most of the time for everyone, no matter how pious or devout. We tend to "coast" in our spiritual life and not to make a positive effort to be all that we can be, so to speak.
The Church in her wisdom, recognizes this, and so makes something compulsory, lest this tendency to laxity cause many to not attend church. Is that a good thing all in all or a bad one? Is it a "net gain"? Of course it is good. It's better to have someone be in Church, even though they are not perfectly motivated from the heart and soul, than not to be there, and sitting at home watching Tim Russert or Brit Hume.
It's another "both/and" scenario: I don't have to disagree with you about the ideals of the Christian life: wholehearted service to God and completely pure motivation: doing everything for the right reasons, by God's grace. I also don't have to quibble with the Church's wisdom in requiring church attendance, for the sake of the vast majority of Christians who are usually coasting in their spiritual life.
Both are good. We all should strive for the ideal, and pray for God's grace to achieve it, but we should also be glad that many a Joe Q. Catholic is in the pews even though he is there because he has to be there, not because he wants to be. Oftentimes, Protestants are so far into the ethereal, ideal realm of pure, sublime Christianity that they neglect to see that God in His mercy accepts millions upon millions of His followers as they are, warts and all.
Some of that flows from the nature of the (flawed) theology of Protestantism: particularly extrinsic justification (and for the Calvinist, total depravity).
Expanded and bad links removed: 12 February 2015.