(b) Reasons that excuse from part of the ecclesiastical precept do not excuse from all of it. Thus, those who are unable to hear Mass are not thereby justified in doing servile work, those who can hear the essential part of Mass (Consecration and Communion), but not the other parts, should hear the essential part; those who can hear Mass only on one Sunday a year are not excused on that Sunday.
(c) Reasons that excuse from the ecclesiastical precept do not excuse from the divine precept (see 2575) of worshipping God. Hence, those who are really obliged to work every Sunday should sanctify the Lord’s Day by whatever private prayer or devotion they can substitute. Some authors very rightly believe that those who can never go to Mass on Sunday are held by divine law to hear Mass on weekdays three or four times a year at least, when this is possible (see 2148, 2180).
2586. The Second Precept of the Church.—This precept commands that on all Fridays of the year and certain other specified days (unless they fall on a holyday outside of Lent) every baptized person who has completed the age of seven and has attained the use of reason shall abstain from eating flesh meat and from drinking the broth or soup made from flesh meat (Canons 1250-1254).
(a) Under the name flesh are included all land and warm-blooded animals (i.e., mammals and birds). The law does not include aquatic animals (i.e., fishes, clams, oysters and other shellfish, lobsters, shrimps, crabs and other crustaceans), nor cold-blooded animals (i.e., reptiles, snails and amphibians, such as frogs, tortoises). Some authors include under aquatic animals otters, beavers, seals, walruses, loons, and coots, though generally the birds are regarded as flesh. In doubt whether a food is fish or flesh, it may be judged to be fish, for in doubts laws are to be interpreted benignly.
(b) Under the name meat are included all the parts of an animal (i.e., its flesh, blood, marrow, brains, lard, meat extracts, mince-pie, pepsin) but not its fruit (e.g., eggs, milk, and things made from milk, such as butter, cheese).
(c) Under the name broth is included any liquid made from the juice of meat, such as beef tea, chicken broth, mutton soup, gravy, etc. But the law does not forbid condiments made from animal fats (e.g., margarin).
2587. Obligation of the Second Precept of the Church.—(a) Origin of the Obligation.—In substance this precept is of the natural law, but in details (time, manner, etc.) it is of ecclesiastical law (2468 b) and has come down from customs that began in the first ages of Christianity. The church regulation on abstinence is most wise and moderate: the foods forbidden are those whose deprivation is a mortification to most persons, and at the same time a great benefit to spiritual and bodily health; the times appointed are few but appropriate (viz., days of sorrow, special prayer, penance, preparation, such as Fridays, Ember Days, Lent, vigils), and they are so distributed as to sanctify by mortification each week and each season of the year. True, no food is evil in itself (Matt., xv. 11; I Cor., viii, 8; I Tim., iv. 3; Col., ii. 16), but just as the physician can forbid certain foods to his patient for the sake of temporal good, so for the sake of spiritual good God forbade to Adam the fruit of one tree and to the Jews the flesh of certain animals; and the Church from the days of the Apostles (Acts, xv. 29) has exercised the same right.
(b) Gravity of the Obligation.—The abstinence required by the Second Precept is a grave duty, because the Church makes it the necessary act of the necessary virtue of abstemiousness and a serious duty of obedience. But not every transgression is a serious injury to the spirit of this law, and hence some sins against it are venial. Grave matter is such a quantity of forbidden food as gives considerable nourishment, and hence for practical purposes the rule may be given that flesh meat which weighs two ounces (or, according to others, what would be the size of a walnut or of a small hen’s egg) is grave matter. Some hold for a more liberal interpretation when the food is not strictly flesh meat, and believe that liquid from meat is not grave matter at any time, or at least when it weighs less than four ounces. Vegetables cooked or seasoned with meat or meat juice are also considered light matter. He who eats meat twice on a Friday or other abstinence day commits two sins, just as he who works twice on a Sunday or holyday commits two sins. It is commonly held that many venial sins against abstinence committed on the same day coalesce to form grave matter, but on account of the separation between the eatings a larger amount is necessary for grave matter.
(c) Exceptions to the Obligation.—Those are not bound to observe a day of abstinence who have been exempted by indult (Canon 1253), who have been dispensed by the Ordinary, pastor or superior (Canon 1245), or who are excused on account of real impossibility (e.g., the poor, the sick, those obliged to perform very hard work, those who are morally forced to eat meat but not as a sign of contempt of the law). Persons dispensed from abstinence may not eat meat oftener than once a day on fast days, unless they have a special grant. The faithful should be guided by the Lenten regulations of their dioceses, and in doubt they should consult their pastors.
2588. The Obligation of Fasting.—The Second Precept also commands that on the weekdays of Lent and certain other specified days (holydays outside Lent excepted) every baptized person between the ages of twenty-one years completed and sixty years begun shall eat not more than one full meal a day (Canon 1251).