The religious relationship between creatures and the Creator is not exhausted in an external and social communication that results in mediation. The priesthood is precisely a mediation between God and men exercised by a minister chosen and often consecrated by a particular rite.
Man, individually and socially, feels the need of a mediator for his relationship with God. This need perhaps has its roots in the consciousness of sin, more deeply in the feeling of his own nothingness before the Infinite. To adequately respond to this feeling, a mere man, even if surrounded by holiness, could not suffice; a superhuman man was needed, one who would transcend the condition of simple man.
Here lies the origin and the reason for the existence of the priesthood of Christ, which exhausts and surpasses every other priesthood, achieving the perfect mediation between man and God in the work of reconciling the one with the other.
That Christ is a priest is a truth explicitly revealed by God. Already in the Old Testament the future Messiah is solemnly announced as a Priest: "The Lord has sworn and will not repent: You are a priest forever according to the order of Melchizedek" (Ps. 110).
St. Paul takes up and develops the motif of this divine dignity, demonstrating its realization in Jesus, of whom he outlines the dignity and priestly function in that epistle to the Hebrews which may be called the code of the redeeming priesthood of Christ (v. Ebrei, Epistola agli).
Priest and victim together: "to be offered as a lamb and to offer as a priest." But the question of the priesthood of Christ was debated and deepened at the time of the Nestorian heresy (5th century) and in the other Christological controversies that dragged on until the 7th century. See, for example, St. John Chrysostom, in his commentary on the epistle to the Hebrews. But more than he, St. Cyril of Alexandria had to address the subject in his controversy with Nestorius and other Antiochenes, who, by dividing Christ God (the Word) from Christ Man, refused to recognize any priestly function in the former, but only in the latter. St. Cyril, by virtue of the profound hypostatic union and the consequent communication of idioms, claims the title of pontiff and priest for the Word himself insofar as he is united with human nature.
According to divine Revelation, Christ is certainly a Priest and Pontiff who accepts the Sacrifice as God and offers it as man, being at the same time both offerer and victim: "For us He is victor and victim, and therefore victor because victim; for us He is priest and sacrifice, and therefore priest because sacrifice" (St. Augustine, Confess., X, 43, 69; cf. id., De Civ. Dei, X, 20).
The reactions against this truth transmitted in the early Christian generations stem from errors concerning the person of Christ. The magisterium of the Church adopts the doctrine of St. Cyril of Alexandria, who in his anathematisms relates mediation to priesthood and attributes both to the Word according to human nature, recalling divine Revelation: "There is one mediator between God and men, the man Christ Jesus" (1 Tim. 2:5). The Council of Trent reconfirms the truth of the priesthood of Christ and develops it in the Eucharistic sphere (sess. XXII, cap. 1). Pius XI in the encyclical Quas primas (AAS, 17 [1925], pp. 598 ff.) unites in a single treatment the Kingship and the priesthood of the Redeemer.
II. THEOLOGY OF THE PRIESTHOOD OF CHRIST.
Theology, in possession of this abundant testimony of written and oral Revelation, flourishes and develops, following the thought of the Fathers, in the scholastic era. The fruit of this theological elaboration is found in St. Thomas (v. especially: Summa Theol., 3a, q. 22).
1. Perfection and characteristics of the priesthood of Christ
The Angelic Doctor studies the nature and perfection of the priesthood of Christ in the light of the concept of mediation. The true priest is the mediator between God and men (ibid., q. 22, a. 1), insofar as his office consists in communicating divine things to men and human things to God. Given original sin, priestly mediation assumes a reparative function, which is concentrated in the expiatory Sacrifice. Now Christ is the perfect mediator, as revealed in St. Paul (1 Tim. 2:5). Indeed, the mediator is truly such if, according to the line of being, he is situated between two extreme terms (ontological mediation) and if he is capable of uniting by communicating goods to each other (moral mediation). Christ as God-Man fully realizes these conditions in Himself: He is distinguished from the Father and the Holy Spirit personally and, according to the assumed human nature, is distant from God; moreover, He is distinguished and distant from men, because His human nature is united hypostatically with the Word and is full of incomparable grace and holiness. On the other hand, consubstantiality unites Him with the Father and the Holy Spirit in the unity of nature, and consubstantiality with us makes Him a man of our specific nature. For this double bond, Christ is in the position to fulfill the conciliatory function between God and men, which is the proper end of the Incarnation. He is therefore the perfect mediator, of whom the prophets and priests of the Old Testament were but approximate images (Summa Theol., 3a, q. 26, a. 1-2). By logical consequence, Christ is constituted a priest of singular perfection, just as singular is the hypostatic union upon which His mediation and His priesthood rest.The essential characteristics of this priesthood can be reduced to three. a) Christ is constituted a priest not by an added vocation, but by virtue of the hypostatic union. Thus Christ does not become a priest but is born a priest when the Word becomes flesh. The function of mediation and priesthood certainly does not suit the Word as such, because that function necessarily implies a certain inferiority with respect to God. For this reason St. Paul warns that Christ is a mediator as man (1 Tim. 2:5), and the Fathers and theologians, with St. Thomas, declare that the subject of the priesthood of Christ is His humanity (Summa Theol., 3a, q. 22, a. 3, ad 1). But it is also true that that humanity cannot be thought of or subsist independently of the Word who assumed II. Already St. Augustine had anticipated the difficulties when he wrote (Serm., 12, 21): "Behold the mediator: divinity without humanity is not a mediator, humanity without divinity is not a mediator, but between divinity alone and humanity alone the human divinity and the divine humanity of Christ is the mediator." More concisely St. Thomas (loc. cit.): "Although Christ was not a priest insofar as He is God, but insofar as He is man, yet He was one and the same priest and God." b) Christ is priest and victim together (Summa Theol., 3a, q. 22, a. 2). The end of the priesthood and of the sacrifice is to elevate the soul and unite it with God. Sin had dug an abyss between creatures and the Creator: an abyss that no man could have bridged, because sin, having in itself an infinite moral dimension, required an infinite reparation. The solution to the problem is the Incarnation, by which a mediator capable of suffering in His humanity and capable of infinitely satisfying through His sufferings, because He is a Divine Person subsisting in that human nature, comes to be constituted. Christ, the mediator and priest, offers the only Sacrifice worthy of God, namely His humanity immolated on the Cross for the redemption of men. c) The priesthood of Christ is eternal, as St. Paul affirms. One must distinguish between the eternity of state and the eternity of function. The priestly state of Christ, deriving from the very hypostatic union, which is indissoluble, is evidently eternal. But the priestly function is not eternal, at least not in its principal act, which is the sacrifice. Christ offered Himself once and for all, and therefore in His glorious life He can no longer celebrate the sacrifice of Himself.
2. The priestly acts of Jesus Christ
As Mediator between God and men, the priest, as has been said, carries out his mission by offering human things to God and divine things to men. Two gestures: one ascending, the other descending. The first is expressed especially in sacrifice accompanied by prayer; the second in the distribution of divine gifts (graces).a) The priestly act par excellence is sacrifice (v.). It is a matter of faith that Jesus Christ, by His death on the Cross, offered the Father a true and perfect sacrifice (Council of Ephesus, anathema, 10; Council of Trent, sess. XXII, cann. 3-4). Above all, St. Paul insists on the sacrificial character of the Saviour’s death: Christ, our Pasch, has been immolated (ἐνθύν, a technical term proper to sacrificial language: 1 Cor 5:7); Christ gave Himself for us as an oblation and a victim (ἐπάσφαγον καὶ αἱ θυσίαι = offering and bloody victim; Eph 5:2); Christ is a victim for sin (ἀμαρτία: 2 Cor 5:21), a propitiatory victim (ἀμαρτία: Rom 3:24). In the Letter to the Hebrews (chs. 9-10), the Sacrifice of Jesus is exalted above all the sacrifices of the Old Testament. St. Peter likewise (1 Pet 1:18-19) speaks of Jesus as the immaculate Lamb who has redeemed us by His precious blood. The unanimous thought of the Fathers confirms this: Origen, *In Num.*, 24:1: “In all these victims there is one Lamb, who was able to take away the sin of the whole world, and therefore the other victims ceased, because this was such a victim that one alone sufficed for the salvation of the whole world.” St. Augustine, *De Trin.*, 4:13: “By His death, indeed, having offered one most true sacrifice...” St. Cyril of Alexandria, *Adv. Nestor.*, 3:1: “He offered Himself to the Father for us as a most adorable victim”; and in the 10th anathema: “He offered Himself for us to God and the Father as a sweet-smelling savour.” St. Thomas subjects the death of Christ to profound theological meditation (*Summa Theol.*, 3a, q. 22, aa. 4-5). The free obedience and, above all, the love with which Christ faced the death foreordained by the Father are the formal reason for the Sacrifice of the Cross. The crossbeam is transformed into an altar, and death takes on a sacrificial character of infinite value because of the love with which Christ accompanies His immolation (ibid., q. 48, a. 13).
In vain did Faustus Socinus in his work *De Jesu Christo Salvatore*, II, and Auguste Sabatier in his work *La doctrine de l'expiation et son évolution historique* (Paris 1903) attempt to strip the death of Christ of its sacrificial value. Their theory, fundamentally heretical, remains refuted by what has been set forth above regarding the doctrine revealed by God in the Old and New Testaments and defined by the infallible magisterium of the Church.
Yet even among Catholics the question of Christ’s sacrifice has been variously agitated in modern times. It is especially the French school of the Oratory (Cardinal de Ligny, Condren, Olier) that treats with fervent mysticism of the sacrifice and of Christ’s sacrifice, speaking insistently of a celestial, eternal sacrifice of Christ.
With the best theology, under the guidance of St. Thomas, one may conclude with these firm points: a) Christ the Priest has celebrated no other true and proper sacrifice than that of the Cross, of which the Eucharistic sacrifice is an anticipation and a continuation. That sacrifice is essential in heaven and is not a glorified humanity and therefore impossible, incapable of further sacrificial treatment, but rather definitively stripped of every character of victimhood. c) Therefore Christ in heaven, while remaining in His priestly being, does not formally continue His sacrifice either as oblation or as immolation, but applies its fruits to souls, by which means they attain eternal life. This is the consummated sacrifice, admitted in heaven even by St. Thomas (*Summa Theol.*, q. 22, a. 5), who explains the eternity of Christ the Priest inasmuch as “the power of that victim” (of Christ crucified) “once offered remains forever” (ibid., ad 2). d) The priestly function of Christ in heaven is exercised, according to the text of Heb 7:25, by means of intercession, which theologians interpret in various ways. St. Thomas, *In Ap. ad Hebr.*, comments thus: “He intercedes for us first by His humanity, which He assumed for us, revealing it; likewise by the desire of His most holy soul, which He had for our salvation, expressing it, with which He intercedes for us.” Thus the application of the fruits of Redemption, which is a priestly function, takes place in heaven by virtue of the humanity assumed by the Word and immolated on the Cross for the redemption of men. A humanity that speaks for itself, with its glorious scars and the ardent desire of the soul for our salvation.
For the Eucharistic Sacrifice and its connection with that of the Cross V. MASS.
3. The second priestly act of Christ is prayer. The Gospel attests that Jesus prayed frequently in public and in private; indeed, it tells us that He often spent entire nights in prayer. As a seal upon this life of intimate converse with the Father, St. John has preserved in his Gospel the sublime prayer of the Last Supper, a priestly prayer and testament of love. And St. Paul in Hebrews recalls the fervent supplications of Jesus the Priest to the Father: “Who in the days of His flesh, with strong crying and tears, offered up prayers and supplications to Him that was able to save Him from death, and was heard for His reverence” (Heb 5:7). St. Thomas (*Summa Theol.*, 3a, q. 21) treats this delicate subject with his usual perspicacity. Prayer, he says, is a manifestation of the will made to God so that it may be fulfilled. This is possible only in a creature, which is not capable of bringing about by itself all that it wills.
Christ therefore prays insofar as He is man. Yet by virtue of the hypostatic union the prayer of Christ’s soul is proper to the Person of the Word, and thus it must be said that the Word prays according to the assumed humanity, in a manner analogous to what has been said of Christ as Mediator and Priest.
Jesus the Priest prayed throughout His earthly life for us men, but the efficacy of His prayer, like that of His redemptive work, does not save all. His prayer, though most efficacious, is bound up with the mystery of predestination and the reconciliation of grace with free will.
4. The third priestly act of Christ is the distribution of grace and glory. The active mediation is at once Redemption and the sacrifice of Christ. Now Redemption is the production of grace through the satisfaction and merit of Christ crucified, grace ordered to the attainment of eternal life.
Here the question of the causality of grace recurs. It is known that the principal cause of grace is God alone and thus Christ insofar as He is the Son of God; but the instrumental cause is the assumed humanity as an organ of the Word. And since Christ is Priest according to His human nature, which He offered in bloody sacrifice on the Cross, it is evident that the distribution of grace is a proper act of Christ the Priest. Every soul that is sanctified and saved passes through Calvary and enters heaven by the merits and action of Christ the Priest and Victim. The Sacraments are an extension of the priestly humanity of the Redeemer; it is Christ who baptizes, who absolves, who repeats the gesture of His immolation at the altar. The sacramental character is a configuration of the Christian to Christ the Priest.
III. CONCLUSION
Rightly does St. Paul reduce Christianity to a soteriology and concentrate this soteriology in the mystery of the Cross. Christ, God-Man, Mediator, Priest, and Victim for the redemption of the human race: this is the Christian religion.The Sacrifice of Christ the Priest is a journey of God toward man and of man toward God, a journey that traverses the cycle of creation, by which God, impelled by infinite love, in a certain sense goes forth from Himself to return to Himself. This journey is Christ Himself, Who called Himself “the Way.” He stretches between the world and God to reconcile and unite them in love through His priestly act.