Not only should we keep Sunday well ourselves, but we should endeavor to have it so kept by others. We must be careful, however, not to fall into the mistake of some who wish the Sunday to be kept as the Pharisees of old kept the Sabbath, telling us we must not walk, ride, sail, or take any exercise or enjoyment on that day. This is not true, for Our Lord rebuked the Pharisees for such excessive rigor; God made the Sunday for our benefit, and if we had to keep it as they say we must, it would be more of a punishment than a benefit.
355 Q. How are we to worship God on Sundays and holy days of obligation? A. We are to worship God on Sundays and holy days of obligation by hearing Mass, by prayer, and by other good works.
356 Q. Are the Sabbath day and the Sunday the same? A. The Sabbath day and the Sunday are not the same. The Sabbath is the seventh day of the week, and is the day which was kept holy in the Old Law; the Sunday is the first day of the week, and is the day which is kept holy in the New Law.
“Old Law” means the law that God gave to the Jews, the New Law, the law that Our Lord gave to Christians.
357 Q. Why does the Church command us to keep the Sunday holy instead of the Sabbath? A. The Church commands us to keep the Sunday holy instead of the Sabbath because on Sunday Christ rose from the dead, and on Sunday He sent the Holy Ghost upon the Apostles.
We keep Sunday instead of Saturday also to teach that the Old Law is not now binding upon us, but that we must keep the New Law, which takes its place.
358 Q. What is forbidden by the Third Commandment? A. The Third Commandment forbids all unnecessary servile work and whatever else may hinder the due observance of the Lord’s day.
359 Q. What are servile works? A. Servile works are those which require labor rather of body than of mind.
“Servile”—that is, work which was formerly done by the slaves. Therefore writing, reading, studying, etc., are not servile, because they were not the works of slaves.