Venerable Pope Pius XII : No sooner, in fact, "is the Word made flesh"[13] than he shows Himself to the world vested with a priestly office, making to the Eternal Father an act of submission which will continue uninterruptedly as long as He lives: "When He cometh into the world he saith. . . 'behold I come . . . to do Thy Will."[14] This act He was to consummate admirably in the bloody Sacrifice of the Cross: "It is in this will we are sanctified by the oblation of the Body of Jesus Christ once."At the Last Supper He celebrates a new Pasch with solemn rite and ceremonial, and provides for its continuance through the divine institution of the Eucharist. On the morrow, lifted up between heaven and earth, He offers the saving sacrifice of His life, and pours forth, as it were, from His pierced Heart the sacraments destined to impart the treasures of redemption to the souls of men. All this He does with but a single aim: the glory of His Father and man's ever greater sanctification.

16. Thus we observe that when God institutes the Old Law, He makes provision besides for sacred rites, and determines in exact detail the rules to be observed by His people in rendering Him the worship He ordains. To this end He established various kinds of sacrifice and designated the ceremonies with which they were to be offered to Him. His enactments on all matters relating to the Ark of the Covenant, the Temple and the holy days are minute and clear. He established a sacerdotal tribe with its high priest, selected and described the vestments with which the sacred ministers were to be clothed, and every function in any way pertaining to divine worship.[11] Yet this was nothing more than a faint foreshadowing[12] of the worship which the High Priest of the New Testament was to render to the Father in heaven.

17. No sooner, in fact, "is the Word made flesh"[13] than he shows Himself to the world vested with a priestly office, making to the Eternal Father an act of submission which will continue uninterruptedly as long as He lives: "When He cometh into the world he saith. . . 'behold I come . . . to do Thy Will."[14] This act He was to consummate admirably in the bloody Sacrifice of the Cross: "It is in this will we are sanctified by the oblation of the Body of Jesus Christ once."[15] He plans His active life among men with no other purpose in view. As a child He is presented to the Lord in the Temple. To the Temple He returns as a grown boy, and often afterwards to instruct the people and to pray. He fasts for forty days before beginning His public ministry. His counsel and example summon all to prayer, daily and at night as well. As Teacher of the truth He "enlighteneth every man"[16] to the end that mortals may duly acknowledge the immortal God, "not withdrawing unto perdition, but faithful to the saving of the soul."[17] As Shepherd He watches over His flock, leads it to life-giving pasture, lays down a law that none shall wander from His side, off the straight path He has pointed out, and that all shall lead holy lives imbued with His spirit and moved by His active aid. At the Last Supper He celebrates a new Pasch with solemn rite and ceremonial, and provides for its continuance through the divine institution of the Eucharist. On the morrow, lifted up between heaven and earth, He offers the saving sacrifice of His life, and pours forth, as it were, from His pierced Heart the sacraments destined to impart the treasures of redemption to the souls of men. All this He does with but a single aim: the glory of His Father and man's ever greater sanctification.