45 To these unanimous prayers, pious works of penance should be added. For the effect of devotion to prayer is this: "The soul is sustained, is prepared for arduous deeds and ascends to things Divine. The effect of penance is that we control ourselves, especially our body, which is, because of original sin, most rebellious against reason and the law of the Gospel. It is clear that these two virtues are intimately connected, help one another, and combine to withdraw man, who was born for Heaven, from transitory things, and carry him close to heavenly intimacy with God" (Leo XIII, encyc. Octobri mense , Sept. 22, 1891; Acta Leonis XIII, XI, p. 312).
Source: Fulgens Corona (Vatican.va)