In common Christian usage, the depriving of self of certain pleasures and satisfactions when the privation is undertaken for the purpose of self-discipline, mortification, or sharing more intimately in the cross of Christ. In its New Testament foundation, however, the term appears to have a more profound meaning. Jesus said: "If anyone wishes to come after me, let him deny himself …" (Mt 16.24). This is not simply a denying of some gratification to oneself, but a denying of oneself. It is, in a sense, a refusal to recognize one's own personal self, and a man who denies himself in this way says in effect, "I do not know myself." The same Greek verb ἀπαρνέομαι, is used here that is employed in connection with Peter's denial of Christ, when he said that he did not know Him. To deny oneself in this sense amounts to giving up, in a way, one's own personality and to emptying one's self completely in order to live in the unselfish manner of Christ. This sense of the term includes the refusal to gratify one's own inclinations at certain times and in certain matters, but it reaches beyond this to include the total unselfishness toward which particular exercises of self-denial should aim.
Self-denial is necessary because of the effects of original sin. Because of his inheritance from Adam (Eph4.21–24), man is from birth inclined to evil, disposed to error, attracted to unreasonable pleasures. These effects of original sin remain in the baptized, and self-denial helps to nullify them and makes the soul more disposed to God's action. To obey the Commandments requires in some measure this denial of self, and a man without such power cannot do even what is necessary for salvation.
Many examples of the practice of self-denial are to be found in the lives of the saints, and in some cases self-denial was carried to an extreme because their love of God was such that they were not satisfied with half measures. In some instances these extremes might have been exaggerated by pious hagiographers, who sometimes emphasized the extraordinary so strongly that it cannot be seen in proper perspective. Moreover, not all the extremes even in the lives of the saints are defensible, and some of the saints themselves acknowledged that they had been imprudent, as, for example, St. Francis of Assisi, who declared toward the end of his life that he had been somewhat too hard on Brother Ass. In any case, most authorities on the spiritual life caution against undertaking extraordinary measures of self-denial or mortification without the approval of a prudent confessor or director.
All moralists teach that some self-denial is required for all Christians and that greater self-denial is necessary for a life of extraordinary sanctity. The teaching of Molinos, who counseled against self-denial, was condemned, as were the teachings of the Jansenists, who overemphasized its importance.
Bibliography: r. garrigou-lagrange, The Three Ages of the Interior Life, tr. m. t. doyle, 2 v. (St. Louis 1947–48) 1:275–298. a. tanquerey, The Spiritual Life, tr. h. branderis (2d ed. Tournai 1930; repr. Westminster, MD 1945) 362–391. a. royo, the Theology of Christian Perfection, ed. and tr. j. aumann (Dubuque 1962) 217–317. j. lebreton, "La Doctrine de renoncement dans le NT," Nouvelle Revue Théologique (1938) 65 385–412.
"Self-Denial." New Catholic Encyclopedia. . Encyclopedia.com. (November 21, 2018). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/self-denial
"Self-Denial." New Catholic Encyclopedia. . Retrieved November 21, 2018 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/self-denial