In the New Testament, Jesus brings to light the profound motive for fasting, condemning the attitude of the Pharisees, who scrupulously observed the prescriptions of the law, but whose hearts were far from God. True fasting, as the divine Master repeats elsewhere, is rather to do the will of the Heavenly Father, who “sees in secret, and will reward you” (Mt 6,18). He Himself sets the example, answering Satan, at the end of the forty days spent in the desert that “man shall not live by bread alone, but by every word that proceeds from the mouth of God” (Mt 4,4). The true fast is thus directed to eating the “true food,” which is to do the Father’s will (cf. Jn 4,34). If, therefore, Adam disobeyed the Lord’s command “of the tree of the knowledge of good and evil you shall not eat,” the believer, through fasting, intends to submit himself humbly to God, trusting in His goodness and mercy.
The practice of fasting is very present in the first Christian community (cf. Acts 13,3; 14,22; 27,21; 2 Cor 6,5). The Church Fathers, too, speak of the force of fasting to bridle sin, especially the lusts of the “old Adam,” and open in the heart of the believer a path to God. Moreover, fasting is a practice that is encountered frequently and recommended by the saints of every age. Saint Peter Chrysologus writes: “Fasting is the soul of prayer, mercy is the lifeblood of fasting. So if you pray, fast; if you fast, show mercy; if you want your petition to be heard, hear the petition of others. If you do not close your ear to others, you open God’s ear to yourself” (Sermo 43: PL 52, 320. 322).
In our own day, fasting seems to have lost something of its spiritual meaning, and has taken on, in a culture characterized by the search for material well-being, a therapeutic value for the care of one’s body. Fasting certainly bring benefits to physical well-being, but for believers, it is, in the first place, a “therapy” to heal all that prevents them from conformity to the will of God. In the Apostolic Constitution Pænitemini of 1966, the Servant of God Paul VI saw the need to present fasting within the call of every Christian to “no longer live for himself, but for Him who loves him and gave himself for him … he will also have to live for his brethren“ (cf. Ch. I). Lent could be a propitious time to present again the norms contained in the Apostolic Constitution, so that the authentic and perennial significance of this long held practice may be rediscovered, and thus assist us to mortify our egoism and open our heart to love of God and neighbor, the first and greatest Commandment of the new Law and compendium of the entire Gospel (cf. Mt 22, 34-40).
The faithful practice of fasting contributes, moreover, to conferring unity to the whole person, body and soul, helping to avoid sin and grow in intimacy with the Lord. Saint Augustine, who knew all too well his own negative impulses, defining them as “twisted and tangled knottiness” (Confessions, II, 10.18), writes: “I will certainly impose privation, but it is so that he will forgive me, to be pleasing in his eyes, that I may enjoy his delightfulness” (Sermo 400, 3, 3: PL 40, 708). Denying material food, which nourishes our body, nurtures an interior disposition to listen to Christ and be fed by His saving word. Through fasting and praying, we allow Him to come and satisfy the deepest hunger that we experience in the depths of our being: the hunger and thirst for God.
At the same time, fasting is an aid to open our eyes to the situation in which so many of our brothers and sisters live. In his First Letter, Saint John admonishes: “If anyone has the world’s goods, and sees his brother in need, yet shuts up his bowels of compassion from him – how does the love of God abide in him?” (3,17). Voluntary fasting enables us to grow in the spirit of the Good Samaritan, who bends low and goes to the help of his suffering brother (cf. Encyclical Deus caritas est, 15). By freely embracing an act of self-denial for the sake of another, we make a statement that our brother or sister in need is not a stranger. It is precisely to keep alive this welcoming and attentive attitude towards our brothers and sisters that I encourage the parishes and every other community to intensify in Lent the custom of private and communal fasts, joined to the reading of the Word of God, prayer and almsgiving. From the beginning, this has been the hallmark of the Christian community, in which special collections were taken up (cf. 2 Cor 8-9; Rm 15, 25-27), the faithful being invited to give to the poor what had been set aside from their fast (Didascalia Ap., V, 20,18). This practice needs to be rediscovered and encouraged again in our day, especially during the liturgical season of Lent.
From what I have said thus far, it seems abundantly clear that fasting represents an important ascetical practice, a spiritual arm to do battle against every possible disordered attachment to ourselves. Freely chosen detachment from the pleasure of food and other material goods helps the disciple of Christ to control the appetites of nature, weakened by original sin, whose negative effects impact the entire human person. Quite opportunely, an ancient hymn of the Lenten liturgy exhorts: “Utamur ergo parcius, / verbis cibis et potibus, / somno, iocis et arctius / perstemus in custodia – Let us use sparingly words, food and drink, sleep and amusements. May we be more alert in the custody of our senses.”
Dear brothers and sisters, it is good to see how the ultimate goal of fasting is to help each one of us, as the Servant of God Pope John Paul II wrote, to make the complete gift of self to God (cf. Encyclical Veritatis splendor, 21).
[Pope Benedict, Message for Lent 2009]