By exercising control over natural desires and appetites, Catholics strengthen their will and prepare themselves to resist temptations and selfish impulses. This spiritual discipline allows them to focus on their relationship with God and cultivate a life of virtue.
According to a document from Secretariat of Divine Worship According to the United States Conference of Catholic Bishops, since ancient times, Christians have practiced penance, both communally and individually, following the example of Jesus Christ, who fasted and prayed for forty days in the desert (Mc. 1, 13). Furthermore, he points out that this practice seeks to imitate Christ and achieve spiritual plenitude, which is pointed out by Saint Paul in Ephesians 4, 13.
As the Catechism of the Catholic Church recalls in its numeral 1430, Jesus’ call to conversion and penance focuses mainly on the “conversion of the heart”, rather than on performing external acts, since the latter are not useful if they are not accompanied by a true interior conversion. However, the Catechism emphasizes that, when there is truly a conversion of heart, that attitude can be expressed in “visible signs, gestures and works of penance,” as the prophets and Jesus taught.