The first Note is that the exterior penances are done chiefly for three ends: First, as satisfaction for the sins committed; Second, to conquer oneself – that is, to make sensuality obey reason and all inferior parts be more subject to the superior; Third, to seek and find some grace or gift which the person wants and desires; as, for instance, if he desires to have interior contrition for his sins, or to weep much over them, or over the pains and sufferings which Christ our Lord suffered in His Passion, or to settle some doubt in which the person finds himself.[…] Third Note. The third: When the person who is exercising himself does not yet find what he desires – as tears, consolations, etc., – it often helps for him to make a change in food, in sleep and in other ways of doing penance, so that he change himself, doing penance two or three days, and two or three others not. For it suits some to do more penance and others less, and we often omit doing penance from sensual love and from an erroneous judgment. (Saint Ignatius of Loyola, Spiritual Exercises, Tenth Addition – Rule of Penance)

Sixth addition: I will lay aside during the first week all joyful thoughts, such as the glorious Resurrection of Jesus Christ. This thought would dry up the tears which I ought at this period to shed over my sins. I must rather call up thoughts of death and judgment, in order to assist my sorrow.
Seventh addition: For the same purpose, I will shut out the daylight. Only allowing sufficient light to enter my room to enable me to read and take my meals.
Eighth addition: I will carefully avoid all laughter, or anything which can lead to it.
Ninth addition: I will not look at anyone, unless obliged to salute them or say adieu. (Saint Ignatius of Loyola, Spiritual Exercises, Additions 6-9)

[To have the true sentiment which we ought to have in the Church Militant] Seventh Rule. To praise Constitutions about fasts and abstinence, as of Lent, Ember Days, Vigils, Friday and Saturday; likewise penances, not only interior, but also exterior. (Saint Ignatius of Loyola, Spiritual Exercises, Rules for the Sentire cum Ecclesia)

The most grave disease by which our age is oppressed, and at the same time the fruitful source of all the evils deplored by every man of good heart, is that levity and thoughtlessness which carry men hither and thither through devious ways.  […] Now, if we would cure this sickness from which human society suffers so sorely, what healing remedy could we devise more appropriate for our purpose than that of calling these enervated souls, so neglectful of eternal things, to the recollection of the Spiritual Exercises? And, indeed, if the Spiritual Exercises were nothing more than a brief retirement for a few days, wherein a man removed from the common society of mortals and from the crowd of cares, was given, not empty silence, but the opportunity of examining those most grave and penetrating questions concerning the origin and the destiny of man: ‘Whence he comes; and whither he is going’; surely, no one can deny that great benefits may be derived from these sacred exercises. (Pius XI, Encyclical Mens sostra, no. 4, December 20, 1929)

Now it is recognized that among all the methods of ‘Spiritual Exercises’ which very laudably adhere to the principles of sound Catholic asceticism one has ever held the foremost place and adorned by the full and repeated approbation of the Holy See and honored by the praises of men, distinguished for spiritual doctrine and sanctity, has borne abundant fruits of holiness during the space of well nigh four hundred years; we mean the method introduced by Saint Ignatius of Loyola, whom we are pleased to call the chief and peculiar Master of ‘Spiritual Exercises’ […] And in very deed, the excellence of spiritual doctrine altogether free from the perils and errors of false mysticism, the admirable facility of adapting the exercises to any order or state of man, whether they devote themselves to contemplation in the cloisters, or lead an active life in the affairs of the world, the apt co-ordination of the various parts, the wonderful and lucid order in the meditation of truths that seem to follow naturally one from another; and lastly the spiritual lessons which after casting off the yoke of sin and washing away the diseases inherent in his morals lead a man through the safe paths of abnegation and the removal of evil habits. (Pius XI, Encyclical Mens nostra, no. 22, December 20, 1929)

Effectively, what are you now if not representatives of a profoundly Catholic people whose ardent and lively perseverance in the faith is due perhaps, among other reasons, to the blossoming of the Spiritual Exercises of Saint Ignatius in your country? […] Great was your valor in the hour of trial, when, in the midst of persecution, your fidelity and spirit of sacrifice was written with the very blood of your heroic brothers. You put the resolutions of the Exercises into practice well, demonstrating their fulfillment not in life, but in death! (Pius XII. Speech to pilgrims from Spain on a pilgrimage organized by the Society for Parish Exercises, October 24, 1948)

But your example also serves us in commending the efficacy of the Exercises of Saint Ignatius, when fidelity to its spirit and method are conserved, as it is among you, thanks be to God. It is not true that the method has lost its efficacy, or that it no longer corresponds to the needs of modern man. Actually, the sad reality is that the liqueur loses its potency when diluted in the waters of over-adaptation, and the machine loses its strength when basic gears of the Ignatian system are dismantled. The Exercises of Saint Ignatius will always be one of the most efficacious means for spiritual renovation and proper order in the world, but on condition that they continue to be authentically Ignatian. (Pius XII. Speech to pilgrims from Spain, October 24, 1948)

Not that We should little worth the methods of exercises used by others, but in those that are carried out according to the Ignatian method, the entire scheme is so wisely arranged, each part leading so well to the next, that where there is no opposition to divine grace, there is, so to say, a radical renewal of the individual and his total submission to the divine will. Prepared in this manner for a life of action, Ignatius concentrated his efforts on forming his chosen companions, desiring their exemplary obedience to God and His Vicar, the Roman Pontiff, and that they consider obedience to be the main characteristic of his Company. Consequently, he not only desired that his followers enhance their spiritual fervor through the Exercises, but he also armed them with this instrument so that they themselves might employ it in their efforts to lead straying souls back to the Church, thus submitting them entirely to the power of Christ. (Pius XI. Apostolic Letter Meditantibus nobis, December 3, 1922)

We affirm without a doubt that it is always, in all cases and for all people, there will be a participation in that fruit which consists of ‘ordering one’s life’ (Spirit. Exer., 21) after ‘conquering oneself”, and stripping oneself ‘of all disordered affections…in order to seek and fulfill the divine will in the ordering of one’s life’ (Ibid 1); always derives from them a greater practice of prayer and examination of conscience, along with an increased desire for mortification, with a deeper moral formation, the person is consequently more disposed to ‘love and serve his divine majesty in all things. (Ibid., 233)’ (Pius XII, Speech, June 15, 1956)

I hope that your own lives and the lives of those with whom you have contact will benefit from the deeper knowledge and understanding that you are gaining of the decisive and self-sacrificing spirituality of Saint Ignatius of Loyola. It is a form of spirituality that has stood the test of centuries and is daily demonstrating its vitality and relevance to our own times and needs. (John Paul II, General audience, January 28, 1981)

Wherefore before all things it is necessary that the mind, assisted by solitude should devote itself to the sacred meditations, leaving aside all the cares and solicitudes of daily life. For as that golden book, the ‘Imitation of Christ’, clearly teaches: ‘The devout soul makes progress in silence and in peace’ (De Imit. Chr., L.I., c. 206). For this reason, although we regard those meditations as worthy of praise and pastoral approval in which many make the exercises together in public — for these have received many blessings from God — still we most strongly recommend those Spiritual Exercises which are made in private, and are called ‘closed.’ (Pius XI, Encyclical Mens nostra, no. 13, December 20, 1929)

The seeking of God through prayer has to be preceded and accompanied by an ascetical struggle and a purification from one’s own sins and errors, since Jesus has said that only ‘the pure of heart shall see God’ (Mt 5:8). […] The passions are not negative in themselves (as the Stoics and Neo-Platonist thought), but their tendency is to selfishness. It is from this that the Christian has to free himself in order to arrive at that state of positive freedom which in classical Christian times was called ‘apatheia,’ in the Middle Ages ‘impassibilitas’ and in the Ignatian Spiritual Exercises ‘indiferencia.’ This is impossible without a radical self-denial, as can also be seen in Saint Paul who openly uses the word ‘mortification’ (of sinful tendencies).Only this self-denial renders man free to carry out the will of God and to share in the freedom of the Holy Spirit. (Congregation for the Doctrine of the Faith, Letter to the Bishops of the Catholic Church, October 15, 1989)

Furthermore, you realize that spiritual exercises contribute greatly to the preservation of the dignity and holiness of ecclesiastical orders. Therefore do not neglect to promote this work of salvation and to advise and exhort all clergy to often retreat to a suitable place for making these exercises. Laying aside external cares and being free to meditate zealously on eternal divine matters, they will be able to wipe away stains caused by the dust of the world and renew their ecclesiastical spirit. (Pius IX, Encyclical Qui pluribus, no. 29, November 9, 1846)

For by daily experience, beloved, it is proved that the mind’s edge is blunted by over-indulgence of the flesh, and the heart’s vigor is dulled by excess of food, so that the delights of eating are even opposed to the health of the body, unless reasonable moderation withstands the temptation and the consideration of future discomfort keep from the pleasure. For although the flesh desires nothing without the soul, and receives its sensations from the same source as it receives its motions also, yet it is the function of the same soul to deny certain things to the body which is subject to it, and by its inner judgment to restrain the outer parts from things unseasonable, in order that it may be the oftener free from bodily lusts, and have leisure for Divine wisdom in the palace of the mind, where, away from all the noise of earthly cares, it may in silence enjoy holy meditations and eternal delights. (Saint Leo the Great, Sermon 19: De jejunio decimi mensis, no. 1)

This involves maintaining silence and an attitude of humble adoration before God, for the divine word reveals its depths to those who, through silence and mortification, are attentive to the Spirit’s mysterious action. While the requirement of regular silence establishes times when human words must be stilled, it points to a style marked by great moderation in verbal communication. If it is perceived and lived in its profound sense, it slowly teaches the interiorization by which the monk opens himself to a genuine knowledge of God and man. (John Paul II, Message to the Abbot of Subiaco, no. 4, July 7, 1999)

Today it is difficult to create ‘zones of isolation and silence’, for we are continually caught up in mechanism of occupations, in the tumult of happenings, and the attraction of the means of communication. Consequently, interior peace is threatened and the elevated thoughts that should direct human existence encounter obstacles. It is difficult, but it is important to know how to achieve it. (John Paul II, General audience, words to the youth, March 18, 1981)

But as time went on men were still held by the desire of placid solitude wherein away from witnesses the soul might give attention; nay more, it is found that in the most turbulent ages of human society men athirst for justice and truth were the more vehemently urged by the Divine Spirit seek the solitude ‘in order being free from bodily desire they might more often be intent on the divine wisdom in the court of the mind where all the tumult of earthly cares being silent, they may rejoice in holy mediations and eternal delights.’ (Pius XI, Encyclical, Mens nostra, no. 6, December 20, 1929)

Ours is not an age which fosters recollection; at times one has the impression that people are afraid of detaching themselves, even for a moment, from the mass media. For this reason, it is necessary nowadays that the People of God be educated in the value of silence. Rediscovering the centrality of God’s word in the life of the Church also means rediscovering a sense of recollection and inner repose. (Benedict XVI, Apostolic Exhortation Verbum Domini, no. 66, September 30, 2010)

Communities which are entirely dedicated to contemplation, so that their members in solitude and silence, with constant prayer and penance willingly undertaken, occupy themselves with God alone, retain at all times, no matter how pressing the needs of the active apostolate may be, an honorable place in the Mystical Body of Christ, whose ‘members do not all have the same function’ (Rom 12:4). For these offer to God a sacrifice of praise which is outstanding. Moreover the manifold results of their holiness lends luster to the people of God which is inspired by their example and which gains new members by their apostolate which is as effective as it is hidden. Thus they are revealed to be a glory of the Church and a well-spring of heavenly graces. (Vatican Council II, Decree Perfectae Caritatis, no. 7, October 28, 1965)

The consecration of religious enters into this way of his; it cannot be a reflection of his consecration if its expression in life does not hold an element of self-denial. […] It is true that much of today’s penance is to be found in the circumstances of life and should be accepted there. However, unless religious build into their lives ‘a joyful, well-balanced austerity’ (ET 30) and deliberately determined renunciations, they risk losing the spiritual freedom necessary for living the counsels. Indeed, without such austerity and renunciation, their consecration itself can be affected. This is because there cannot be a public witness to Christ poor, chaste, and obedient without asceticism. (Sacred Congregation for Religious and for Secular Institutes, Essential Elements in the Church´s teaching on Religious Life, no. 31, May 31, 1983)

‘Original sin’ is the hereditary but impersonal fault of Adam’s descendants, who have sinned in him (Rom 5: 12). It is the loss of grace, and therefore of eternal life, together with a propensity to evil, which everybody must, with the assistance of grace, penance, resistance and moral effort, repress and conquer. The passion and death of the Son of God has redeemed the world from the hereditary curse of sin and death. Faith in these truths, which in your country are today the object of vile derision of Christ’s enemies, belongs to the inalienable treasury of Christian revelation. (Pius XI, Encyclical Mit Brennender Sorge, no. 25, March 14, 1937)

For since we are all sinners and laden with many faults, our God must be honored by us not only by that worship wherewith we adore His infinite Majesty with due homage, or acknowledge His supreme dominion by praying, or praise His boundless bounty by thanksgiving; but besides this we must need make satisfaction to God the just avenger, ‘for our numberless sins and offenses and negligences.’ To Consecration, therefore, whereby we are devoted to God and are called holy to God, by that holiness and stability which, as the Angelic Doctor teaches, is proper to consecration (S.Th. II-II q. 81, a. 8. c.), there must be added expiation, whereby sins are wholly blotted out, lest the holiness of the Supreme Justice may punish our shameless unworthiness, and reject our offering as hateful rather than accept it as pleasing. Moreover this duty of expiation is laid upon the whole race of men since, as we are taught by the Christian faith, after Adam’s miserable fall, infected by hereditary stain, subject to concupiscence and most wretchedly depraved, it would have been thrust down into eternal destruction. (Pius XI, Encyclical Miserentissimus Redemptor, no. 6, May 8, 1928)

Having, therefore, been thus justified and having been made the ‘friends of God’ and ‘his domestics’ (Jn 15:15, Eph 2:19), ‘advancing from virtue to virtue’ (Ps 83:8), ‘they are renewed’(as the Apostle says) ‘from day to day’ (2Co 4:16), that is, by mortifying the members of their flesh (Col 3:5), and by ‘presenting them as instruments of justice’ (Rom 6:13, Rom 6:19), unto sanctification through the observance of the commandments of God and of the Church; in this justice received through the grace of Christ ‘faith cooperating with good works’ (Jas 2:22), they increase and are further justified [can. 24 and 32], as it is written: ‘He that is just, let him be justified still’ (Apoc 22:11), and again: ‘Be not afraid to be justified even to death’ (Sir 18:22), and again: ‘You see, that by works a man is justified and not by faith only’ (Jas 2:24). (Denzinger-Hünermann 1535. The Council of Trent, Session VI, Ch. 10, January 13, 1547)

But the body is to be mortified and the sensual appetites to be repressed not only by fasting, and particularly, by the fasts instituted by the Church, but also by watching, pious pilgrimages, and other works of austerity. By these and similar observances is the virtue of temperance chiefly manifested. In connection with this subject, Saint Paul, writing to the Corinthians, says: ‘Every one that striveth for the mastery, refraineth himself from all things; and they indeed that they may receive a corruptible crown, but we an incorruptible one’ (1 Co 9: 24). A little after he says: ‘I chastise my body and bring it into subjection, lest, perhaps, when I have preached to others, I myself should become a castaway’ (1 Co 9: 27). And in another place he says: ‘Make not provision for the flesh in its concupiscence’ (Rom 13:14). (Catechism of the Council of Trent, Part II – The Sixth Commandment)

Jesus Christ taught us self-discipline and self-denial when He said: ‘If anyone wishes to come after me, let him deny himself and take up his cross daily and follow me’ (Lk 9:23). Yet there are many people, alas, who join instead the immoderate quest for earthly pleasures, thus debasing and weakening the nobler powers of the human spirit. It is all the more necessary, therefore, for Christians to repudiate this unworthy way of life which gives frequent rein to the turbulent emotions of the soul and seriously endangers its eternal salvation. They must repudiate it with all the energy and courage displayed by the martyrs and those heroic men and women who have been the glory of the Church in every age of her history. (John XXIII, Encyclical Paenitentiam agere, no. 36, July 1, 1962)

But we must remind you here of an important truth: the Christian conception of life demands of all — whether highborn or lowly — a spirit of moderation and sacrifice. That is what God calls us to by His grace. There is, alas, a spirit of hedonism abroad today which beguiles men into thinking that life is nothing more than the quest for pleasure and the satisfaction of human passions. This attitude is disastrous. Its evil effects on soul and body are undeniable. Even on the natural level temperance and simplicity of life are the dictates of sound policy. On the supernatural level, the Gospels and the whole ascetic tradition of the Church require a sense of mortification and penance which assures the rule of the spirit over the flesh. (John XXIII, Encyclical Mater et magistra, nos. 234-235, May 15, 1961)

Here, then, is the paradoxical consequence: faced with ever greater and more complex machines, the human being ends up finding himself morally ever more reduced and insignificant, at the mercy of the dark powers of his own subconscious, or by the equally  deceptive and forceful power of mass psychology. To have his liberty restored, man primarily requires assistance from on high, which he may obtain through prayer, in order to re-establish his interior world damaged by sin. He needs, moreover, a strong and determined will, capable of escaping from the false suggestions of sin, in order to bravely undertake the paths of goodness: and this entails the generous practice of renunciation and sacrifice, that is, it demands the courage to do penance, to obtain that self-control, which permits easy domination of self in harmony with the most profound truth of ones being.  (John Paul II, Angelus, February 24, 1985)

Furthermore, through the action of grace, the believer who makes generous efforts in the practice of penance is gradually identified with Christ, who is man’s true liberator. ‘Where the spirit of the Lord is, there is freedom’ (2Cor 3:17). Today the penitential practices ordered by the Church are so limited, that they do not fulfill at all the duty and the necessity that each person to do penance. The rest is left the generous initiative of each one. Consequently, it is necessary that the maturity of conscience among the faithful urges them to spontaneously seek, rather to create within the limits of their liberty the forms and ways of penance according to their own personal necessities of liberation from sin, of purification and of perfection. (John Paul II, Angelus, March 10, 1985)

Jesus often went off alone to pray (cf. Mt. 14:23). The ability to handle a healthy solitude is indispensable for caring for one’s interior life. Here we are speaking of a solitude filled with the presence of the Lord who puts us in contact with the Father, in the light of the Spirit. In this regard, concern for silence and looking for places and times of ‘desert’ are necessary for the priest’s permanent formation, whether in the intellectual, spiritual or pastoral areas. In this regard too, it can be said that those unable to have a positive experience of their own solitude are incapable of genuine and fraternal fellowship. (John Paul II, Apostolic Exhortation Pastores dabo vobis, no. 74, March 25, 1992)

The priestly life certainly requires an authentic spiritual intensity in order to live by the Spirit; (Gal 5: 25) it requires a truly virile asceticism — both interior and exterior —   in one who, belonging in a special way to Christ, has in Him and through Him ‘crucified the flesh with its passions and desires’ (Gal 5:24), not hesitating to face arduous and lengthy trials in order to do so (1Cor 9:26-27). (Paul VI, Encyclical Sacerdotalis caelibatus, no. 78, June 24, 1967)

And even for men individually, penance is the foundation and bearer of true peace detaching them from earthly and perishable goods, lifting them up to goods that are eternal, giving them, even in the midst of privations and adversity, a peace that the world with all its wealth and pleasures cannot give. One of the most pleasing and most joyous songs ever heard in this vale tears is without doubt the famous “Canticle of the Sun” of Saint Francis. Now the man who composed it, who wrote it and sang it, was one of the greatest penitents, the Poor Man of Assisi, who possessed absolutely nothing on earth, and bore in his emaciated body the painful Stigmata of His Crucified Lord. Prayer, then, and penance are the two potent inspirations sent to us at this time by God, that we may lead back to Him mankind that has gone astray and wanders about without a guide: they are the inspirations that will dispel and remedy the first and principal cause of every form of disturbance and rebellion, the revolt of man against God. (Pius XI, Encyclical Caritate Christi compuli, no. 27-28, May 3, 1932)

Having joy set before Him, He endured the Cross, and He bade us deny ourselves. The very dignity of human nature depends upon this disposition of mind. For, as even the ancient Pagan philosophy perceived, to be master of oneself and to make the lower part of the soul, obey the superior part, is so far from being a weakness of will that it is really a noble power, in consonance with right reason and most worthy of a man.[…] We would remind those persons of this truth who desire a kind of Christianity such as they themselves have devised, whose precepts should be very mild, much more indulgent towards human nature, and requiring little if any hardships to be borne. They do not properly understand the meaning of faith and Christian precepts. (Leo XIII, Encyclical Tametsi futura, nos. 6,10,  November 1,  1900)

When the Apostles asked the Savior why they had been unable to drive the evil spirit from a demoniac, Our Lord answered: ‘This kind is not cast out but by prayer and fasting’ (Mt 17:20). So, too, the evil which today torments humanity can be conquered only by a world-wide crusade of prayer and penance. We ask especially the Contemplative Orders, men and women, to redouble their prayers and sacrifices to obtain from heaven efficacious aid for the Church in the present struggle. Let them implore also the powerful intercession of the Immaculate Virgin who, having crushed the head of the serpent of old, remains the sure protectress and invincible  Auxilium Christianorum (Help of Christians). (Pius XI, Encyclical Divini Redemptoris, no. 59, March 19, 1937)