“Except you do penance, you shall all likewise perish.” – St. Luke xiii.5.
"Lent is a time of penance and prayer, established by the Church as a preparation for the feast of Easter. Lent lasts forty days; and is on that account called also the holy quadragesima. During this time the Church obliges us to observe abstinence and fasting, so as to honor and imitate the fasting of our Lord, who passed forty days and forty nights in the desert, without tasting food, beginning thus the painful penance he came to perform on earth, for the redemption of our sins. My children, by fasting we deprive ourselves of part of our food, by abstinence we refrain from partaking of anything in the shape of flesh-meat. These practices have been for centuries considered as most approaching the spirit of penance; and you no doubt remember that in olden times the Ninevites tried, by ordering a public fast, to avert the wrath of God from their city.
During the early ages of the Church, Christians used frequently to fast, some did so all the year round; and now there still exist holy monks who practice fasting and abstinence with the same severity.
In our days, on the contrary, my children, generally speaking, these rules of the Church are not strictly observed; though we are all still in the same great need of penance, and the Church, in its indulgence, has made the accomplishment of this duty much less difficult than it formally was. Then, only one single meal was taken during the twenty-four hours; now it is allowed to add what is called the collation, which is a second meal, but a very light one.
Abstinence binds children above seven years of age; but the law of fasting is not imposed on children who are in need of very substantial food. But at the age of twenty-one, you will be subjected to it, and even then, if your health be delicate, you can obtain a dispensation from your confessor or the Priest of your parish. And on this point, let me tell you, my children, that you have no right to judge the motives which may lead your parents and persons who surround you to fall short in the fulfillment of these duties of fasting and abstinence. On this, you must make no reflections; you must merely make up your minds that when you are older, you will obey, to the utmost of your power, every commandment of the Church.
For the present, young as you are, it is already your duty, to do penance of some kind, during Lent, for your sins; God frees no one from this obligation, not even children of your age. Do not let this thought alarm you; God does not ask you to do anything very difficult, and to you penance will not be very trying. When you have offended your mother, you have no great difficulty, I suppose, in showing her your sorrow and in trying to atone for your ill-behavior.
Well, during this holy time, you must act in the same way towards our Lord. Be more attentive while saying your prayers, more fervent during holy mass, more obedient at home. The poor ought to have a larger share of your little savings, and you must say to God: “O Lord, vouchsafe to accept these efforts and slight sacrifices till I am able to keep thy other commandments.” This, my children, should be your penance during Lent."
Source: The Catholic Instructor, An Educational Library of Ready Reference (1910 published by The Office of Catholic Publications, New York), under the chapter “Readings for Each Sunday in the Year: The Catholic Mother to Her Children” by The Countess de Flavigny. [Originally published under the approbation of His Grace the Archbishop of Paris, and adopted by the University, and endorsed by the Cardinal Archbishop of Tours, and the last Cardinal Manning, Archbishop of Westminster.]