Very little of substance has been written on this subject, yet there is ample basis for this truth. The two best treatments that I found in my research are these intriguing sources: Marie, l’Eglise et le Sacerdoce by Rene Laurentin,2 and Marie et Notre Sacerdoce by Emile Neubert, S.M.3

The focus of this presentation is Maria, Mater et socia Christi sacerdotis.

A balanced approach is essential. The eccelesiotypical representation of the mystery of Mary should not overshadow the Christotypical. One aspect should not diminish the other. This is not an either-or situation, but one of both-and. It is a matter of particular emphasis on the subject under consideration.

The Evidence of Tradition
This question has seldom been studied in a theologically scientific manner. It is specifically the subject of Laurentin’s masterful work previously mentioned, the result of his doctoral thesis.

In the early ages of Christianity scarcely anyone searched for a quality specifically sacerdotal in the functions of the Mother of Jesus. “The use of a sacerdotal vocabulary in reference to Mary arrives slowly, and, as it were, by exception . . . . The theological themes answering to this use are little developed; the idea of an oblation by Mary, which would suggest her sacerdotal role in the clearest manner possible, had not been conceived.”4 Preaching and the hymns of the seventh to ninth centuries witness to “a tendency to confer sacerdotal titles on Mary,” but do not indicate “the existence of the idea of a Marian priesthood.”5

The idea of Mary’s oblation first appeared in the subsequent period, which lasted until 1600.6 St. Bernard, in the twelfth century, had already clearly expressed this idea.7 In the next century writings attributed to St. Albert the Great considered this oblation sacerdotal. Later it was determined that a still unidentified Pseudo-Albert was responsible for these ideas. Employing the principle that Mary possesses all the graces and prerogatives of other rational creatures to a superior degree, Pseudo-Albert proposed to show that she had received with a unique fullness all that belongs to the various offices in the Church’s hierarchy.8 His successors take the view, and noted that in this position the comparison is made between Mary’s sacerdotal role and that of ordained priests. 

In the seventeenth century, Salazar and other Spanish theologians compare her role with that of Christ and identify it with her redemptive mission.9

In the same century, another line of thought associated with Berulle and the French School of Spirituality appeared, and continued throughout the eighteenth century. While its inspiration originates in the Spanish school, this new line of thought overshadows Salazar’s interpretation, due principally to Olier and the seminary of Saint-Sulpice. In the French school, Mary was invoked and contemplated as the model of the priest, and was honored as “Virgo sacerdos, the Virgin Priest.”10

The Marian writings from the early 19th century are vacuous and sentimental. By the middle of the century a rebirth occurred. Theologians began to restore to Mariology its theological content, and to connect again with the movements of the seventeenth century. Once again mediation, co-redemption, and the sacerdotal aspect of Mary’s mission gained ascendancy in their studies. 11

Around 1870 the idea of living as a victim began to gain popularity among a number of generous souls, especially women religious, who proposed to assist the priests through their prayers and sacrifices. They thought naturally of Mary praying and offering herself for and with her Son, and they loved to consider her as the sacerdotal virgin or the Virgin Priest. This devotion aroused great enthusiasm, and was at times expressed in formulas scarcely theological.12

In 1873 Blessed Pius IX approved a book written by Msgr. van den Berghe entitled Mary and the Priesthood. In it the author employs the term “Virgin Priest.” The pope justified its use by the fact of Mary’s role in the sacrifice of Jesus as divini sacrificii socia. In 1906 Saint Pius X granted an indulgence for a prayer containing the invocation. “Mary, Virgin Priest, pray for us.” Pius X explained this designation by stating with Saint Antoninus of Florence that, although Mary had never received the sacrament of Holy Orders, she nevertheless possesses as much dignity and grace as are found in the priesthood.

But during the reign of Pius X, the Holy Office issued a decree stating that “the representation of Mary clothed in sacerdotal vestments was disapproved.” In reality, the representation in question was that of an orante, which some persons mistook for Mary vested as a priest. In 1926-27 the Holy Office again opposed the propagation of devotion to the “Virgin Priest.” Even though only the picture and the spread of this devotion have been forbidden, Rome is evidently unfavorable to the title of “Virgin Priest,” since it might lead poorly instructed Catholics to believe that Mary had received the sacrament of Holy Orders. Yet these decrees of the Holy Office in no way affect the pronouncements of Popes Blessed Pius IX and Saint Pius X that Mary was “an associate of the Divine Sacrifice,” and that she was enriched with “as much dignity and grace as are found in the priesthood.”13

These interventions by Rome are rather negative because, from the viewpoint of the sacerdotal quality of Mary’s functions, they determine what the Blessed Virgin is not; namely, the equivalent of an ordained priest. On the positive side, the exact notion of what the sacerdotal quality of her activity is continues to be the topic of theological discussions. Progress can be noted in a clear understanding of this question.

The search for what is properly sacerdotal in Mary’s mission must be directed to an immediate examination of two of Mary’s prerogatives: that she is the Mother of Christ, our High Priest, and that she is the Associate of Christ, our High Priest, in His sacrifice.

Mary, the Mother of Christ, Our High Priest
The Son of God became incarnate to be the Mediator between God and man, to be our High Priest. Every priest is taken from among men.14 Christ is not a priest in virtue of His divine Sonship, for how could He be mediator between Himself and people? Christ is a priest in virtue of His human nature, which is hypostatically united to His divinity.

Christ received His human nature from Mary, who, in giving it to him, contributed to the establishment of the Son of God as our High Priest. Christ’s priestly vocation was received from His Father; His sacerdotal anointing is the grace of the hypostatic union, the gift of His Father, or more exactly of the Holy Trinity. What enables the Son of God to be our High Priest, namely His humanity, came to Him through Mary.

Mary furnished the material cause. But she did not supply it blindly. She knew that the Messiah, whose Mother she was to become, was to be the High Priest of a new priesthood. “Like Melchizedek you are a priest forever.”15 She knew too that the priesthood of Christ would depend on her reply, and therefore she was a fully conscious, free, and responsible cause of that priesthood. Mary is the Mother of God, of our Creator, of our Lawgiver, of our Rewarder. Had she refused the invitation of Gabriel, the Son of God would still be our God, Creator, Lawgiver, and Rewarder, but not our Savior and our Priest.

Mary, the Associate of Christ, Our High Priest
Christian tradition informs us that Mary participated in the prerogatives and in the functions of Christ according to the measure and insofar as her condition as creature and woman permitted her to share in these privileges of an incarnate God.16 She is, according to the expressive phrase of Pseudo-Albert, the socia Christi, who has been given to Him as a helper like to Himself, adjutorium simile sibi. This is her role in the work of the Redemption, in the distribution of grace, in the kingship of Christ. Such also is her role in regard to Christ’s priesthood. Therefore, the study of this office of the Virgin Mother must be made in reference to the priesthood of Christ rather than to the ministry of ordained priests.

The general elements that make a person a priest, as mentioned specifically in the Letter to the Hebrews, are these:

• the priest is taken from among men;
• by a special vocation;
• with a consecration or anointing;
• to be a mediator;
• between God, who is to be appeased,
• and human beings, who are to be reconciled to him;
• by the offering of a sacrifice.

Many Christians, especially those consecrated to God, possess several of these elements. Yet they are not priests because they are unable to offer the Sacrifice of the New Law. The power to offer this Sacrifice constitutes the distinguishing trait of the Christian priest.

A sacrifice is any oblation made to God in recognition of His sovereignty. Understood in this sense, anyone can offer sacrifices to God. “Through Him let us continually offer God a sacrifice of praise, that is, the fruit of lips that confess His name. Do not neglect to do good and to share what you have; God is pleased with sacrifices of that kind.”17

Moreover, a sacrifice may consist of something entirely internal: “A burnt offering you would not accept. My sacrifice is a broken spirit; God does not spurn a broken, humbled heart.”18 A sacrifice may also be something both external and internal, in which the external element signifies the internal disposition of the one making the sacrifice.19 In sacrifices offered to God in the name of the people by a man designated to represent them as their mediator, as a priest, these two elements are always present. Such a sacrifice is more in harmony with human nature and is necessary if the people are to participate in the sacrifice. If the interior element is absent, God will reject the material offering as He did so many times when speaking to the Jews through the prophets.

The Christian dispensation is no longer based on the sacrifices of the Mosaic Law. Now God recognizes only the Sacrifice of Christ. “For this reason, when he came into the world, he said: ‘Sacrifice and offering you did not desire, but a body you prepared for me; holocausts and sin offerings you took no delight in.’ Then I said ‘As it is written of me in the scroll, behold I come to do your will, O God.’”20

Now apply these general notions to the priesthood of Christ and to the actions of Mary insofar as she cooperates in His Sacrifice.

Christ is a priest because He is the man-God, our necessary Mediator. He has been called to this office by the Most Holy Trinity, and consecrated in it by the grace of the hypostatic union to appease God’s wrath toward human beings, and to bring them pardon and the grace of adoption. Christ accomplished this by His Sacrifice on the Cross. He did not immolate Himself by His own hands, but He voluntarily abandoned Himself to the hands of His executioners, who, without realizing it, were the instruments of His priestly oblation. It is this immolation (material element) lovingly willed (spiritual element) which comprises His sacerdotal act. Oblatus est quia ipse voluit.

The Blessed Virgin Mary was also taken from among the human race. She was destined from all eternity to be associated with Christ in the work of our Redemption. She was consecrated to this work by the grace of her Divine Maternity, and made Mediatrix of all grace at the side of the Mediator of Justice. Finally, she contributed with Him and through Him to the appeasement of God and the securing of grace for us by her presence at the foot of the Cross (material element), and by the abandonment of her maternal rights over the body of Jesus and by the union of her will and her sufferings with the will and sufferings of her Son in His sacrifice (spiritual element). Note well that in abandoning her maternal rights over the body of Jesus was to immolate Him, just as for Jesus to abandon His body to His executioners was to immolate Himself. Oblatus est quia ipse voluit. “She with her dying Son endured suffering and almost death itself; she renounced her maternal rights over her Son, and to placate Divine Justice to the degree dependent on her, she immolated her Son so that it can be truthfully said of her that, with her Son she redeemed all mankind.”21

Mary is the perfect Associate of Christ in the offering of this redemptive Sacrifice, both in the material element (her presence at the Sacrifice of Calvary) and in the spiritual element (the abandonment of her maternal rights over the life of her Son and the complete union of her will and sufferings with those of Jesus).

Consequently, her cooperation can certainly be termed sacerdotal.

How can this be said of Mary’s cooperation since she did not receive the priestly character? This objection would be serious if Mary’s role were compared to that of the ordained priest. However, in considering this question Mary is compared to Jesus, not to the ordained priest. Jesus did not receive the sacerdotal anointing which made Him the Priest of the New Dispensation: Tu es sacerdos in aeternum. Now at this same instant the Holy Spirit overshadowed Mary making her the Mother of the Son of God as well as his Associate in all His functions, including His Priesthood. As Christ is a priest forever by His hypostatic union which is eternal, so Mary by her Divine Maternity, which will always be hers, is forever associated with Christ the High Priest.

On the one hand this intimate relation between Mary’s association with Christ our Redeemer, and on the other with Christ our High Priest, enables us to determine with precision the sacerdotal nature of Mary’s part in the sacrifice of Calvary, especially since her role as Coredemptrix is the subject of many recent studies.

We know that Mary’s role as Coredemptrix is not identical with that of the Redeemer; it is merely analogous to it. Moreover while her role is necessary, it is so not in itself but only as the loving decree of God. Hers is a secondary role performed not in her own right, but in dependence on the role of Jesus. It is not separate, but is united both in its execution and in its effects with that of the Son. Accordingly, the sacerdotal office of Mary, the cause of her action in the Redemption, is necessary only in view of the will of God, and is subordinate to and dependent on that of Jesus, to which it is united in its accomplishment and its results. Together Jesus and Mary offered the Sacrifice which redeemed us, Christ as second Adam and Mary as adjutorium simile sibi.

Recalling the principle stated at the beginning of this section dealing with Mary as Associate of our High Priest, the difference between the prerogatives of Christ and those of Mary flows not only from her being a creature but also from her being a woman.

It was Mary’s Maternity which conferred this sacerdotal quality on her mission. Her Maternity in relation to Christ made her an Associate in all His functions and permitted her to offer a victim which belonged to her. Her Maternity in relation to us was possible only because she obtained for us the supernatural life through the Sacrifice of her Son. Mary’s sacerdotal role is marked with a feminine and maternal nuance, as are all her other functions.

Though all the constitutive elements of Christ’s priesthood are found in Mary, nonetheless it is not proper to say that she is a priest, for the elements are not in her in an absolute and independent way. She would have been a priest if she had been the only one to offer herself with him and by a title equal to his. But it was Christ who primarily offered Himself. She only united herself to His oblation. Christ’s merit was infinite. Mary’s was necessarily limited, however great it might have been. According to great Marian apostles like Saint Louis de Montfort and Blessed William Joseph Chaminade, all that Mary is, she is in reference to Jesus.22 This is so in her priestly function and in her role as Coredemptrix. She depends fully on Christ, and receives all her efficacy from him. She is not a priest, but is fully priestly; just as she is not a redeemer but is fully Coredemptrix. She is not God, but is fully partaker of the divine life.

Naming Mary’s Sacerdotal Role
If the name “priest” cannot be fittingly applied to Mary, by what name should she be called?

Mary occupies a unique place between Christ and the rest of the human race. Philosophers tell us whatever is individual is inexpressible. This presents the difficulty of expressing the various functions of Mary in precise words. History records instances when only after long discussion and multiplied distinctions was agreement on certain proposed formulas attained. For the uninitiated the expression “Mother of God” might signify quite normally that Mary gave birth to the Holy Trinity; or the word “Coredemptrix” might indicate that she redeemed us by a title equal to Christ’s. It is not surprising, then, that a formula sufficiently clear to everyone and capable of stating exactly Mary’s role in Christ’s priesthood has not been discovered.

Since Mary’s priestly role cannot be explained either in the terms of the priesthood of Christ nor in terms of the ordained minister of the altar, some writers fall back on the “royal priesthood” mentioned by Saint Peter. In comparing the disciples of Christ with unbelievers, Saint Peter tells them: “You are a chosen race a royal priesthood, a holy nation, a people of his own.”23 This royal priesthood enables all the faithful to offer God “spiritual sacrifice acceptable to God through Jesus Christ.”24 This concerns sacrifices in the broad sense of the term, and not with the Sacrifice of the Body and Blood of Jesus Christ. In virtue of their union with Christ in the Mystical Body, all the faithful participate in His perfections and in His priesthood. They share in His priesthood inasmuch as they offer to God the Divine Victim, whom the words of consecration uttered by the priest make present on the altar. They also offer themselves as victims in union with Christ. But they do not participate in it by immolating the Divine Victim, an act possible only to the ordained minister of Christ at the time of consecration. It is this royal priesthood exercised in the highest degree, these writers conclude, that must be attributed to Mary.

But Laurentin and Neubert ask how anyone can subscribe to such an abasement of the sacerdotal role of she who was called by God to Christ’s Associate in the Divine Sacrifice. Those writers reduce Mary’s role to a common category and forget that she is absolutely unique in her functions. These functions are not identical to those of Christ; they are analogous to them. But neither are they identical to those of other persons. Mary’s are of a transcendent order.25

What term, then, can express this unique function of Mary? The best and clearest is the phrase derived from the term socia Christi, applied to her by Pseudo-Albert; that is, the Associate of Christ, our High Priest (socia Christi sacerdotis). 

The word socia in itself is not clearer than the word consors or particeps, and could indicate an equality in the priesthood of Christ and of Mary. Some associates are able to occupy the same rank. However, since the time of Pseudo-Albert, the expression socia Christi has a clearly defined meaning in the history of theology. It designates a secondary action, analogous and united to that of Christ, the action of a “helper like himself.” It is equivalent to the phrase employed by Blessed Pius IX, divini sacrificti socia.

The feminine form socia and the allusion to Eve, the first woman and the mother of the living, refer to a priestly role performed by a woman, by a mother. The sacerdotal aspect of Mary’s mission consists in being mater et socia Christi sacerdotis.

Mary’s Sacerdotal Role Superior to That of the Ordained Priest
Mary’s superiority is manifested in many ways. Mary formed the substance of the Victim, the body of Christ; the priest gives Him only an accidental form, a transitory form, the Eucharistic form.

Mary played an important part in the Sacrifice of the Cross, a part uniquely sorrowful and loving, and lasting thirty-three years. But in the Sacrifice of the Mass the priest is content to lend his hands and tongue to Jesus, the true priest.

Pius X taught that Mary “associated by Christ in the work of salvation, merits for us de congruo what Christ merited for us de condigno.” The priest merits nothing for us in re-enacting the mystery of the Redemption. He simply applies a part of the grace already merited by Jesus and by Mary.

In each Mass the priest renews the offering of the Divine Victim. Christ offered Himself directly and but once on Calvary; but He renews the offering each day through the ministry of the priest. Mary, like Jesus, offered the Divine Victim directly and only once on Calvary. But in heaven Mary renews it at each Mass, since each Mass is the same Sacrifice as that of the Cross. By God’s will, Mary fully cooperated in the Sacrifice of the Cross.

Furthermore, in heaven at the side of the Lamb of God, Mary remains the Associate of His immolation throughout all eternity. The priest must renew the Eucharistic sacrifice each day, and that Sacrifice will cease with the end of time.

When God calls a person to a particular office in the Church, He gives that person the necessary corresponding grace. God gives the priest the special grace he needs for his work. But to Mary He gives more graces than to all priests together.26

Conclusion
Pseudo-Albert summarizes the question when he explains that Mary is set above all members of the hierarchy, even the most distinguished, not only by her Divine Maternity, but also by being at the side of Christ, our High Priest. Pseudo-Albert states: “All members of the Church are members in view of a ministry. But the Blessed Virgin was not chosen by God for a ministry, but to be an Associate and helper, in consortium et adjutorium, as Scripture says, ‘Let us make a helper like unto him.’ The Blessed Virgin is not a substitute; she is a helpmate and an Associate. Beata Virgo non est vicaria sed coadjutrix et socia.”27