Taken from The Sinner’s Guide by the Venerable Louis of Granada chap. 38
Besides these sins against the Commandments of God there are those against the commandments of the Church, which also impose upon us a grave obligation. Such are the precepts to hear Mass on Sundays and holy days of obligation; to confess our sins at least once a year, and to receive the Holy Eucharist at Easter or thereabouts; to pay tithes to our pastor, and to observe the days of fasting and abstinence prescribed by the Church.
The precept of fasting is binding from the age of 21 and upwards; that of abstinence obliges all who have attained the age of reason. The sick, the convalescent, nursing women, women in pregnancy, those whose labors are severe, and those who are too poor to afford one full meal a day, are exempt from the law of fasting. There may be other lawful reasons for dispensation, for which the faithful ought to apply to their pastor or confessor, and not take it upon themselves to set aside the law of the Church.
The difference between abstinence and fasting should be remembered. By fasting we mean eating only one full meal in the day, with a slight collation in the evening. By abstinence we mean giving up the use of flesh-meat. It should be borne in mind, therefore, on Ember days and at other times of fast, that the law is not fulfilled by simply abstaining from meat. Unless you are excused by some of the reasons given above or by dispensation, you must observe the fast by eating only one full meal, with the collation in the evening, and a warm drink, with a cracker or small piece of bread, in the morning.
In regard to hearing Mass, we must endeavor to be present at the Holy Sacrifice not only in body but in mind, with silence and recollection, having our thoughts fixed upon the mystery of the altar, or upon some other pious subject. The recital of devout prayers, especially the Rosary, is an excellent means of keeping ourselves united with God. If we are at the head of a house we must be careful to see that all under our charge hear Mass, not only on Sundays, but also on holy days. Too much laxity regarding holy days is apt to prevail among those who earn their bread by the sweat of their brow. They should remember that the obligation to hear Mass on a holy day is the same as the obligation to hear it on Sunday. Consequently, they must make serious and sincere efforts to comply with this duty. To attend an early Mass may involve the loss of a little sleep, but they should remember that these holy days occur but seldom, and that they must do something to atone for their sins and to merit the kingdom of Heaven.
Parents and employers will have a severe account to render to God if they cause or permit those confided to their care to neglect this sacred duty. When there is a just reason, such as the care of the sick or any other pressing necessity which prevents Mass, we are released from the obligation.
God Bless BJS!!