"Holy days" we are bound to keep holy just in the same manner we do Sundays--that is, by hearing Mass and refraining from servile works. Those who after hearing Mass must attend to business or work on those days should make this known to their confessor, that he may judge if they have a sufficient excuse for engaging in servile works, and thus they will avoid the danger of sinfully violating an important law. There must always be a good reason for working on a holy day. Those who are so situated that they can readily refrain from servile work on holy days must do so. And, where it is possible, the same opportunity must be afforded to their servants. "Of obligation," because there are some holy days not of obligation. We celebrate them, but we are not bound under pain of mortal sin to hear Mass or keep from servile works on such days. For example, St. Patrick's Day is not a holy day of obligation. The great feast of Corpus Christi is not a holy day of obligation. Not satisfied with doing only what the Church obliges us to do on Sundays and holy days, those who really love God will endeavor to do more than the bare works commanded. Sunday is a day of rest and prayer. While we may take innocent and useful amusement, we should not join in any public or noisy entertainments. We may rest and recreate ourselves, but we should avoid every place where vulgar and sometimes sinful amusements, scenes, or plays are presented. Even in taking lawful recreation we may serve God and please Him if we take it to strengthen our bodies that we may be enabled to do the work He has assigned to us in this world.