Ego et Pater unum sumus.
Jo 10,30

«I and the Father are one». This brief statement from John 10:30 is, in Christian theology, one of the cornerstones of the doctrine of the Trinity and Christ’s divinity. Immediately, his interlocutors pick up stones to stone him: they understand that Jesus is asserting his equality with God (John 10:33). Mariology finds in this affirmation the deepest foundation for the title Theotokos: if the Son is one with the Father, then Mary, who gave birth to the Son, is somehow connected to the innermost mystery of divine life.

I. «We are one»: the unity of the Father and the Son in Trinitarian theology

The neutral Greek word hen, «one thing», in John 10:30 is theologically precise: it does not say «we are one» in the sense of personal identity, but «we are one nature`, one essence, one divinity, one being.»

The Council of Nicaea (325) formulated this intuition with the term homoousios, «consubstantial»: the Son is of the same substance as the Father. This definition, which might seem a philosophical technicality, has immense practical and spiritual implications: whoever sees the Son sees the Father (John 14:9). Whoever honors the Son honors the Father (John 5:23). And for Mariology, whoever gave birth to the Son gave birth to one who is consubstantial with the Father.

Athanasius of Alexandria, the great defender of Nicaea, was also one of the first theologians to explicitly explore the connection between homoousios and Theotokos. The argument is simple yet powerful: if the Son is consubstantial with the Father (Nicaea’s definition), and Mary gave birth to the Son (an evangelical fact), then Mary is Theotokos, Mother of God.

The Council of Ephesus (431) formally defined the title Theotokos in this context, not to define Mary but to defend the faith in Christ. The issue at stake was not Mary’s greatness, but the unity of the Son with the Father. Nestorius proposed to call Mary only Christotokos, Mother of Christ, thus separating the human Christ from the divine Person of the Son. Ephesus responded: Mary is Theotokos because the Son she conceived is one with the Father, he is God.

II. Divine motherhood as participation in Trinitarian life

The Definition of Mary as Theotokos

The designation of Mary as “Theotokos” (God-bearer) does not imply that she is the “mother of the Trinity” or that she gave birth to divinity in its essence, which would be absurd. It signifies that the Person she bore is divine: the eternal Son of God took from the Virgin humanity and was born in time as a man, without ceasing to be God. Mary is the mother of the Son as a Person, and this Person is divine, consubstantial with the Father.

The Implication for Mary’s Dignity

The consequence for Mary’s dignity is immense. John Damascene expressed it eloquently, as tradition has preserved: “The Holy Virgin is exalted above all cherubim and seraphim and all created beings, visible and invisible, because she was constituted Mother of the very Creator.” This “exaltation” of Mary is not a devotional hyperbole but a logical outcome of Theotokos: if the Son is consubstantial with the Father, then the dignity of being the Mother of such a Son surpasses all created order.

Theological Tradition and Mary’s Role

The theological tradition, particularly the Franciscan school of Alexander of Hales and Saint Bonaventure, and later the Thomistic school revised by Thomas of Aquino (Cayetan and Domingo de Soto), developed the idea that Mary participates in a created but real and analogical way in the intratrinitarian life. Her relationship with the Father (as the elected daughter), with the Son (as Mother), and with the Holy Spirit (as bride) is not an equal participation among the divine Persons, but it is a real participation that elevates her above all creation.

Saint Louis Maria de Montfort’s Devotion to Mary

Saint Louis Maria de Montfort, in his work *The True Devotion to the Blessed Virgin* (Tratado da Verdadeira Devoção à Santíssima Virgem), further explored these relationships, profoundly influencing modern Catholic spirituality: “God the Father gathered all His waters (…) into Mary, so that rivers of grace might flow from her.” The metaphor points to Mary’s role in distributing the life of the Trinity to humanity: she who received the fullness of grace is the channel through which this grace flows to all children.

III. “That They All Be One”: Mary and the Unity of the Church

John 17:21, in Jesus’ High Priestly Prayer, expresses His desire for unity among His disciples: “Father, that they all be one, as You, Father, are in Me, and I in You, that they also may be in Us.” The unity Jesus seeks is not external uniformity but the unity of love and communion that characterizes the intratrinitarian life, which the Church should reflect in the world.

Maria, as the Mater Ecclesiae, is at the heart of this ecclesial unity. The scene of the Cenacle in Acts 1:14, “all these were devoted to constant prayer, together with Mary, the mother of Jesus,” presents Maria as the gravitational center of the apostolic community before Pentecost. She does not lead externally or institutionally; her presence creates a space of unity, prayer, and openness to the Spirit.

The contemporary ecumenical movement has progressively recognized the ecumenical dimension of Mary. Not by chance, the ecumenical document of the Dombes Group (Marie dans le dessein de Dieu, 1998) devoted an entire chapter to Mary as “figure of unity“: venerated in different ways by the Catholic Church, the Orthodox Church, and many Reformed communities, she can be the point of convergence for the reconstruction of the lost unity of the Church.

This ecumenical dimension of Mariology is not a pragmatic strategy but a theological consequence. If Mary is the figure of the Church, and the Church is called to be “one, holy, catholic and apostolic“, then the veneration of Mary must be, by nature, a factor of unity and not division. Where Mariology divides, it is because it has been distorted in relation to its Christological and Trinitarian foundation. Authentic Mariology, rooted in “Ego et Pater unum sumus”, is necessarily ecumenical.

IV. “Ninguém as arrebatará da minha mão“: segurança trinitária e Assunção

Jn 10:29: “My Father, who gave them to me, is greater than all, and no one can snatch them out of the Father’s hand.” The security of the sheep of the Good Shepherd has a Trinitarian foundation: it rests in the “hand of the Son” and in the “hand of the Father“, which are “one thing” (Jn 10:30). The unity of the Father and the Son is the supreme guarantee of the salvation of the sheep, not because the divine Persons are confused, but because their saving will is one and their power is absolute.

The Assumption of Mary is the most visible fulfillment of this Trinitarian promise for a member of humanity. Mary, who was always in the “hands” of the Father and the Son, from her Immaculate Conception to her faithful service, received the Trinitarian promise in her body and soul: she was “assumed” (taken up, gathered) into the fullness of divine life. No one “snatched” her away because she was in the hands of the Father and the Son.

The iconography of the Coronation of Mary, one of the most frequent Marian themes in Western Christian art, depicts the Father and the Son (and often the Holy Spirit as a dove) crowning Mary in the glory of Heaven. This image visually synthesizes what theology formulates abstractly: Mary’s participation in the Trinitarian life is not merely functional or instrumental; it is a real communion, definitively confirmed by the Assumption. Mary is “within” the Trinitarian life, not as a fourth Person, but as the creature who most fully received and responded to the love of the three Persons.

In the Catholic spiritual tradition, devotion to the Most Holy Trinity and devotion to Mary are inextricably linked. Honoring Mary is honoring the work of the Trinity within creation. Contemplating Mary is contemplating what the three Persons achieved together in the history of salvation. “I and the Father are one,” the statement attributed to Jesus (John 10:30), forms the basis for the Theotokos—the Mother of God—and the full theological and spiritual meaning of her divine motherhood.

References:

• Council of Ephesus, Acts (431).
• St. John Damascene, De Fide Orthodoxa, IV, 14.
• St. Louis Mary de Montfort, True Devotion to Mary, nos. 23-25.
• Group of Dombes, Mary in God’s Design and the Communion of Saints (1998).
• H. U. von Balthasar, Theodramatik, III, “The Action” (1980).