The Mass is the most solemn rite among the offices of the Catholic Church, and embodies the fundamental doctrine upon which the Catholic system of worship mainly rests. It is the chief sacrament, the permanent channel of grace ever kept open between God and his Church. It is an elaborate development of the last supper of Christ with his disciples, and is the fulfilment of the perpetual injunction laid by the Master upon his followers. Developed under the control of the idea of sacrifice, which was drawn from the central conception of the old Jewish dispensation and imbedded in the tradition of the Church at a very early period, the office of the Mass became not a mere memorial of the atonement upon Calvary, but a perpetual renewal of it upon the altar through the power committed to the priesthood by the Holy Spirit. To the Protestant, Christ was offered once for all upon the cross, and the believer partakes through repentance and faith in the benefits conferred by that transcendent act; but to the Catholic this sacrifice is repeated whenever the eucharistic elements of bread and wine are presented at the altar with certain prayers and formulas. The renewal of the atoning process is effected through the recurring miracle of transubstantiation, by which the bread and wine are transmuted into the very body and blood of Christ. It is in this way that the Catholic Church literally interprets the words of Jesus: “This is my body; this is my blood; whoso eateth my flesh and drinketh my blood hath eternal life.” When the miraculous transformation has taken place at the repetition by the priest of Christ’s words of institution, the consecrated host and chalice are offered to God by the priest in the name and for the sake of the believers, both present and absent, for whom prayer is made and who share through faith in the benefits of this sacrificial act. “The sacrifice of the Mass,” says Cardinal Gibbons, “is identical with that of the cross, both having the same victim and high priest—Jesus Christ. The only difference consists in the manner of the oblation. Christ was offered upon the cross in a bloody manner; in the Mass he is offered up in an unbloody manner. On the cross he purchased our ransom, and in the eucharistic sacrifice the price of that ransom is applied to our souls.”[51] This conception is the keystone of the whole structure of Catholic faith, the super-essential dogma, repeated, from century to century in declarations of prelates, theologians, and synods, reasserted once for all in terms of binding definition by the Council of Trent. All, therefore, who assist in this mystic ceremony, either as celebrants and ministers or as indirect participants through faith, share in its supernatural efficacy. It is to them a sacrifice of praise, of supplication, and of propitiation.