99 This offering in fact is not confined merely to the liturgical sacrifice. For the Prince of the Apostles wishes us, as living stones built upon Christ, the cornerstone, to be able as "a holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ." St. Paul the Apostle addresses the following words of exhortation to Christians, without distinction of time, "I beseech you therefore, . . . that you present your bodies, a living sacrifice, holy, pleasing unto God, your reasonable service." But at that time especially when the faithful take part in the liturgical service with such piety and recollection that it can truly be said of them: "whose faith and devotion is known to Thee," it is then, with the High Priest and through Him they offer themselves as a spiritual sacrifice, that each one's faith ought to become more ready to work through charity, his piety more real and fervent, and each one should consecrate himself to the furthering of the divine glory, desiring to become as like as possible to Christ in His most grievous sufferings.
Source: Mediator Dei (Vatican.va)