My dear brothers in the Episcopate,

1. I am impelled to write you this letter-which is both a theological reflection and a pastoral invitation coming from the depths of my heart-first of all, by the Sixteenth Centenary of the First Council of Constantinople, which was held in the year 381. As I pointed out at the beginning of the new year in St. Peter's Basilica, "after the Council of Nicaea this was the second Ecumenical Council of the Church.... To it we owe the Credo that is constantly recited in the Liturgy. A particular heritage of that Council is the doctrine on the Holy Spirit, thus proclaimed in the Latin Liturgy: Credo in Spiritum Sanctum, Dominum et vivificantem. :. qui cum Patre et Filio simul adoratur et conglorificatur, qui locutus est per prophetas."(1)

These words repeated in the Creed by so many generations of Christians will have a particular significance both of doctrine and religious sentiment for us this year and will remind us of the profound bonds that link the Church of today-as we look towards the coming of the third millennium of her life, a life so wonderfully rich and tested, continually sharing in the cross and resurrection of Christ, in the power of the Holy Spirit-with the Church of the fourth century, in the one continuity of her first beginnings, and in fidelity to the teaching of the Gospel and the preaching of the Apostles.

What has just been said suffices to enable us to understand how the teaching of the First Council of Constantinople is still the expression of the one common faith of the Church, of the whole or Christianity. As we confess this faith-as we do every time that we recite the Creed-and as we revive it in the forthcoming centenary commemoration, we wish to emphasize the things which unite us with all our brothers, notwithstanding the divisions that have occurred in the course of the centuries. As we do this, 1600 years after the First Council of Constantinople, we give thanks to God for the truth of the Lord, which thanks to the teaching of that Council, enlightens the paths of our faith, and the paths of life by virtue of that faith. In this anniversary we not only call to mind a formula of faith that has been in force for sixteen centuries in the Church; It the same time we make ever more present to our spirit, in reflection, in prayer, in the contribution of spirituality and theology, that personal divine power which gives life that hypostatic Gift-Dominum et vivificantem- that third Person of the most Holy Trinity who in this faith is shared in by each individual soul and by the whole Church. The Holy Spirit continues to vivify the Church and to guide her along the paths to holiness and love. As St. Ambrose pointed out so well in his work De Spiritu Sancto, "although He is inaccessible by nature, yet He can be received by us, thanks to His goodness; He fills everything with His power, but only the just share in Him; He is simple in His substance, rich in power, present in all, shares that which is His in order to give it to each one, and is wholly present in every place."(2)

2. The memory of the Council of Constantinople, which was the second Ecumenical Council of the Church, makes us, the Christians of the period towards the end of the second millennium, aware of how lively was the need, in the first centuries of the first millennium, among the growing community of believers, to understand and to proclaim correctly, in the confession of the Church, the inscrutable mystery of God in His absolute transcendence: Father, Son and Holy Spirit. This and other key principles of truth and of Christian life first attracted the attention of the faithful; and with regard to these principles there arose numerous interpretations, some of them divergent ones, which made necessary the voice of the Church her solemn witness given in virtue of the promise made by Christ in the Upper Room: "the Counsellor, the Holy Spirit, whom the Father will send in my name...will bring to your remembrance all that I have said to you"(3); He, the Spirit of truth, "will guide you into all the truth."(4)

Therefore, in the present year, 1981, we ought to give thanks to the Holy Spirit in a special way because, in the midst of the many fluctuations of human thought, He has enabled the Church to express her faith, in the manners of expression peculiar to the age, in complete harmony with "all the truth."

"I believe in the Holy Spirit, the Lord, the giver of life, who proceeds from the Father. With the Father and the Son he is worshiped and glorified. He has spoken through the Prophets": these are the words of the Creed of the First Council of Constantinople in 381,(5) that elucidated the mystery of the Holy Spirit and His origin from the Father, thus affirming the unity and equality in divinity of the Holy Spirit with the Father and the Son.

3. As I recall the sixteenth centenary of the First Council of Constantinople, I cannot pass over in silence yet another significant occasion that concerns 1981: this year, in fact, there also occurs the 1550th Anniversary of the Council of Ephesus, which was held in 431. This anniversary is, as it were, overshadowed by the preceding Council, but it too has a particular importance for our faith, and is supremely worthy of being remembered.

In that same Creed, in fact, we recite, in the midst of the liturgical community as it prepares to relive the divine Mysteries, the words: et incarnatus est de Spiritu Sancto ex Maria Virgine, et homo factus est: by the power of the Holy Spirit he became incarnate from the Virgin Mary, and was made man. The Council of Ephesus thus had a value that was above all Christological, for it defined the two natures in Jesus Christ, the divine and the human, in order to state exactly the authentic doctrine of the Church already expressed by the Council of Nicaea in 325, but which had been imperiled by the spread of certain formulas used in the Nestorian teaching. In close connection with these affirmations, the Council of Ephesus also had a soteriological significance, for it illustrated the fact that-as the well- known axiom has it-"what is not assumed is not saved." But just as closely linked with the value of these dogmatic truths was also the truth concerning the Blessed Virgin, called to the unique and unrepeatable dignity of being the Mother of God, the Theotokos, as was so clearly shown principally by the Letter of St. Cyril to Nestorius(6) and by the splendid Formula Unionis of 433.(7) It was a whole hymn raised by those ancient Fathers to the incarnation of the only begotten Son of God, in the full truth of the two natures in the one person; it was a hymn to the work of salvation, accomplished in the world through the working of the Holy Spirit; and all of this could not fail to redound to the honor of the Mother of God, the first cooperator with the power of the Almighty, which overshadowed her at the moment of the Annunciation in the luminous coming of the Holy Spirit.(8) And this is how our brothers and sisters of Ephesus understood it, when, on the evening of June 22, the first day of the Council, celebrated in the Cathedral of the "Mother of God," they acclaimed the Virgin Mary with this title and carried the Fathers in triumph at the end of that first session.

It therefore seems to me very opportune that this ancient Council too, the third in the history of the Church, should be remembered by us in its rich theological and ecclesial context. The most Blessed Virgin is she who, by the overshadowing of the power of the Trinity, was the creature most closely associated with the work of salvation. The incarnation of the Word took place beneath her heart, by the power of the Holy Spirit. In her there dawned the new humanity which with Christ was presented in the world in order to bring to completion the original plan of the covenant with God, broken by the disobedience of the first man. Et incarnatus est de Spiritu Sancto ex Maria Virgine.

4. These two anniversaries, though for different reasons and with differing historical relevance, redound to the honor of the Holy Spirit. All was accomplished by the power of the Holy Spirit. One can see how profoundly these two great commemorations, to which it is proper to make reference in this year of the Lord 1981, are linked to one another in the teaching and in the profession of faith of the Church, of the faith of all Christians. Faith in the Most Holy Trinity: faith in the Father, from whom all gifts come.(9) Faith in Christ, the Redeemer of man. Faith in the Holy Spirit. And, in this light, veneration of the Blessed Virgin, who "by thus consenting to the divine utterance...became the Mother of Jesus. Embracing God's saving will with a full heart and impeded by no sin, she devoted herself totally as a handmaid of the Lord to the person and work of her Son" and "the holy Fathers see her as used by God not merely in a passive way, but as cooperating in the work of human salvation through free faith and obedience."(10) And it is wonderful that, just as Mary awaited with faith the coming of the Lord, so also in this last part of the second millennium she should be present to illuminate our faith as we await this "advent."

All this is for us a source of immense joy, a source of gratitude for the light of this faith, whereby we share in the inscrutable mysteries of God, making them the living content of our souls, expanding thereby the horizons of the understanding of our spiritual dignity and of our individual destinies. And so, these great anniversaries, too, cannot remain for us merely a memory of the distant past. They must take on fresh life in the faith of the Church, they must re-echo anew in her spirituality, indeed they must find an external manifestation of their ever living relevance for the entire community of believers.

5. I write these things in the first place to you, my dear and venerable brothers in the episcopal service. I address myself at the same time to my brother priests, your closest collaborators in your pastoral care in virtute Spiritus Sancti. I address the brothers and sisters of all the religious families of men and women, in the midst of which there should be a particularly lively witness of the Spirit of Christ and likewise a particular love for the mission of her who consented to be the handmaid of the Lord.(11) I finally address myself to all my brothers and sisters of the laity of the Church, who, in professing her faith together with all the other members of the ecclesial community, have so often and for so many generations rendered ever living the memory of the great Councils. I am convinced that they will accept with gratitude the evocation of these dates and anniversaries, especially when together we realize how relevant are, at the same time, the mysteries to which the two Councils gave authoritative expression as long ago as the first half of the first millennium of the history of the Church.

I also venture to hope that the commemoration of the Councils of Constantinople and Ephesus, which were expressions of the faith taught and professed by the undivided Church, will make us grow in mutual understanding with our beloved brothers in the East and in the West, with whom we are still not united by full ecclesial communion but together with whom we seek in prayer, with humility and with trust, the paths to unity in truth. What indeed can more effectively hasten the journey toward that unity than the memory and, at the same time the re-living of that which for so many centuries has been the content of the faith professed in a nun, indeed which has not ceased to be so, even after the sad divisions which have occurred in the course of the centuries?

6. It is therefore my aim that these events should be lived within the whole of their ecclesiological context. We should not merely commemorate these great anniversaries as things that happened in the past: we must give them life in our own times and establish a deep link between them and the life and role of the Church of our period, as that life and role have been given expression throughout the message of the Council of our period, the Second Vatican Council. How deeply rooted in that teaching are the truths defined in the two Councils that we are commemorating! To how great an extent those truths have permeated the Second Vatican Council's central doctrine on the Church! How substantial and constitutive they are for that doctrine! And likewise how intensely these fundamental and central truths of our faith live, so to speak, a new life and shine with a new light throughout the teaching of the Second Vatican Council!

While the chief task of our generation, and perhaps also of future generations in the Church, will be to carry out and make part of life the teaching and guidance of this great Council, the anniversaries this year of the First Council of Constantinople and the Council of Ephesus give us an opportunity for performing this task in the living context of the truth that lasts throughout the ages to eternity.

7. "When the son had accomplished the work that the Father gave him to do on earth (cf. Jn. 17:4), the Holy Spirit was sent on the day of Pentecost, in order that He might continually sanctify the Church and that through Christ those who believe might thus have access in one Spirit to the Father (cf. Eph. 2:18). He is the Spirit of life, a spring of water welling up to eternal life (cf. Jn. 4:14; 7:38-39); through Him the Father gives life to people who are dead because of sin, until the day when, in Christ, He raises to life their mortal bodies (cf. Rom. 8:10-11). The Spirit dwells in the Church and in the hearts of the faithful, as in a temple (cf. 1 Cor. 3:16; 6:19). In them He prays and bears witness to their adoption as children (cf. Gal. 4:6; Rom. 8: 15-18, 26). He guides the Church into all the truth (cf. Jn. 16:13), unifies her in communion and ministry, provides her with varied hierarchic and charismatic gifts, through which He directs her, and adorns her with His fruits (cf. Eph. 4:11-12; 1 Cor. 12:4; Gal. 5:22). He rejuvenates the Church by the power of the Gospel, continually renews her and leads her to perfect union with her Bridegroom. For the Spirit and the Bride say to the Lord Jesus: 'Come' (cf. Rev. 22:17). Thus the universal Church is seen to be 'a people brought into unity from the unity of the Father, the Son and the Holy Spirit.'(12) This is certainly the richest and most synthetic text, although not a unique one, indicating how the truth about the Holy Spirit, to which expression was given so authoritatively 1600 years ago by the First Council of Constantinople, lives with new life and shines with new splendor throughout the teaching of the Second Vatican Council.

The whole work of renewal of the Church, so providentially set forth and initiated by the Second Vatican Council-a renewal that must be both an updating and a consolidation of what is eternal and constitutive of the Church's mission-can be carried out only in the Holy Spirit, that is to say, with the aid of His light and His power. This is important, so important, for the whole of the universal Church and also for each particular Church in its communion with all the other particular Churches. This is important also for the ecumenical process within Christianity and for the Church's path in the modern world, which must extend in the direction of justice and peace. This is important also for activity in favor of priestly or religious vocations, as well as for the apostolate of the laity, as the fruit of a new maturity in their faith.

8. The two phrases in the Niceno-Constantinopolitan Creed, "Et incarnatus est de Spiritu Sancto" and "Credo in Spiritum Sanctum, Dominum et vivificantem," remind us that the greatest work of the Holy Spirit, one to which all the others unceasingly refer as a source from which they draw, is that of the incarnation of the Eternal Word by the power of the Spirit from the Virgin Mary.

Christ, the Redeemer of man and the world, is the center of history: "Jesus Christ is the same yesterday and today and for ever."(13) Our thoughts and our hearts are turned to Him in view of the approaching end of the second millennium separating us from His first coming into the world: but for that very reason they turn to the Holy Spirit, through whose power His human conception took place, and to the Virgin Mary, by whom He was conceived and from whom He was born. The anniversaries of the two great Councils this year direct our thoughts and hearts in a special way to the Holy Spirit and to Mary, the Mother of God. While we recall the joy and exultation that the profession of faith in the divine motherhood of the Virgin Mary (Theotokos) aroused 1550 years ago at Ephesus, we understand that that profession of faith also glorified the particular work of the Holy Spirit, the work composed of both the human conception and birth of the Son of God by the power of the Holy Spirit and, again by the power of the Holy Spirit, the holy motherhood of the Virgin Mary. This motherhood is not only the source and foundation of all her exceptional holiness and her very special participation in the whole plan of salvation; it also establishes a permanent maternal link with the Church, as a result of the fact that she was chosen by the holy Trinity as the Mother of Christ, who is "the Head of the body, the Church."(14) This link was revealed especially beneath the cross, where she, "enduring with her only begotten Son the intensity of His suffering, associated herself with His sacrifice in her mother's heart.... She was given by the same Christ Jesus dying on the cross as a Mother to His disciple, with these words: 'Woman, behold your son!'"(15)

The Second Vatican Council summarizes in felicitous words Mary's unbreakable relationship with Christ and with the Church: "Since it had pleased God not to manifest solemnly the Mystery of the salvation of the human race before He would pour forth the Spirit promised by Christ, we see the Apostles before the day of Pentecost 'with one accord devoting themselves to prayer, together with the women and Mary the mother of Jesus, and with his brethren' (cf. Acts 1:14), and we also see Mary by her prayers imploring the gift of the Spirit, who had already overshadowed her in the Annunciation."(16) With these words the Council text links the two moments in which Mary's motherhood is most closely united with the work of the Holy Spirit: firstly, the moment of the Incarnation, and secondly, that of the birth of the Church in the Upper Room in Jerusalem .

9. Accordingly, all these great and important motives and the coincidence of such meaningful circumstances are reasons for giving particular emphasis throughout the Church this year, which is the jubilee of two events, to the solemnity of Pentecost.

I therefore invite all the Episcopal Conferences of the Catholic Church and the Patriarchates and metropolitan provinces of the Eastern Catholic Churches to send the representatives they wish to Rome for that day, in order that we may together renew the inheritance that we have received from the Pentecost Upper Room in the power of the Holy Spirit. He it is who showed the Church, at the moment of her birth, the way that leads to all nations, all peoples and tongues, and to the heart of every individual.

Finding ourselves gathered in collegial unity, as inheritors of the apostolic solicitude for all the Churches,(17) we shall draw from the abundant source of the same Spirit, who guides the Church's mission on the paths of present-day humanity, at the close of the second millennium after the Word became incarnate by the power of the Holy Spirit in the womb of the Virgin Mary.

10. First, on the morning of the solemnity we shall come together in the Basilica of Saint Peter in the Vatican to sing with all our hearts our belief in Spiritum Sanctum, Dominum et vivificantem...qui locutus est per prophetas.... Et unam sanctam catholicam et apostolicam Ecclesiam. We are prompted to do this by the 1600th anniversary of the First Council of Constantinople. Like the Apostles in the Upper Room and the Fathers of that Council, we shall be brought together by the one who "rejuvenates the Church by the power of the Gospel" and "constantly renews her."(18)

Thus this year's solemnity of Pentecost will be a sublime and grateful profession of the faith in the Holy Spirit, the Lord, the giver of life, that we owe in a particular way to that Council. It will also be a humble and ardent prayer that the Holy Spirit will help us "renew the face of the earth"-among other ways by means of the Church's work of renewal in accordance with the thought of the Second Vatican Council. It will be a prayer that this work may be carried out maturely and in a regular way in all the Churches and Christian communities, and that the work may, first and foremost, be carried out within people's souls, since no true renewal is possible without continual conversion to God. We shall ask the Spirit of Truth that we may, on the path of this renewal, remain perfectly faithful to what the Spirit says to us at the present time in the teaching of the Second Vatican Council, not abandoning this way at the prompting of a certain regard for the spirit of the world. We shall also ask Him who is fons vivus, ignis, caritas (living water, fire and love) to permeate us and the whole Church, and also the human family, with the love that "hopes all things, endures all things" and "never ends."(19)

There is no doubt that at the present stage of the history of the Church and of humanity a special need is felt to go deeper into and give new life to the truth about the Holy Spirit. The commemoration at Pentecost of the sixteenth centenary of the First Council of Constantinople will give us an occasion for doing this, May the Holy Spirit accept our manifestation of faith. In the liturgical function of the solemnity of Pentecost may He accept us as we humbly open our hearts to Him, the Consoler, in whom the gift of unity is revealed and brought to realization.

11. In the second part of the celebration, we shall gather in the late afternoon of the same day in the Basilica of Saint Mary Major. There the morning part will be completed by the thoughts presented by the 1550th anniversary of the Council of Ephesus. We shall also be prompted to do this because by a singular coincidence Pentecost will this year fall on June 7, as it did in 431, when on that solemn day, on which the Council sessions, later postponed to June 22, were to begin, the first groups of bishops began to arrive in Ephesus.

These thoughts will also be reflected on in the light of the Second Vatican Council, with special attention to the marvelous seventh chapter of the Constitution Lumen Gentium. Just as the Council of Ephesus' Christological and soteriological teaching made it possible to confirm the truth about the divine motherhood of Mary, the Theotokos, so too the Second Vatican Council enables us to recall that, when the Church was born by the power of the Holy Spirit in the Upper Room in Jerusalem, she began to look to Mary as the example for her own spiritual motherhood and, therefore, as her archetype. On that day the one whom Paul VI called Mother of the Church irradiated the power of her intercession over the Church as Mother and protected the apostolic zeal by which the Church still lives, generating for God the believers of all times and all geographical areas.

Accordingly, the afternoon liturgy of the solemnity of Pentecost will gather us in the chief Marian Basilica of Rome, in order thus to recall in a special way that in the Upper Room at Jerusalem the Apostles "with one accord devoted themselves to prayer, together with...Mary the mother of Jesus...,"(20) in preparation for the coming of the Holy Spirit. We, too, likewise wish on that important day to devote ourselves with one accord to prayer, together with her who, as Mother of God, is, in the words of the Second Vatican Council's Dogmatic Constitution on the Church, "a type of the Church in the order of faith, charity, and perfect union with Christ."(21) Thus, devoting ourselves to prayer, together with her, and full of trust in her, we shall entrust to the power of the Holy Spirit the Church and her mission among all the nations of the world of today and tomorrow. For we have within us the heritage of those who were commanded by the risen Christ to go into all the world and preach the Gospel to all creation.(22)

On the day of Pentecost, gathered in prayer, together with Mary the Mother of Jesus, they became convinced that they could carry out this command with the power of the Holy Spirit that had come upon them, as the Lord had foretold.(23) On the same day we, their heirs, shall join together in the same act of faith and prayer.

12. Dear brothers,

I know that on Holy Thursday you renew within the community of the presbyterium of your dioceses the memorial of the Last Supper, during which, by the words of Christ and the power of the Holy Spirit, the bread and wine become the body and blood of our Savior, that is to say, the Eucharist of our redemption.

On that day, or also on other suitable occasions, speak to all the People of God about these important anniversaries and events, in order that in every local Church and every community of the Church they may similarly be recalled and lived as they deserve, in the manner that will be decided by the individual bishops in accordance with the indications of the respective Episcopal Conferences or of the Patriarchates or Metropolitan Provinces of the Eastern Churches.

Looking forward eagerly to the celebrations that I have announced, I gladly impart my special apostolic blessing to all of you, venerable and dear brothers in the episcopate, and together with you to your ecclesial communities.

Given in Rome, at St. Peter's on March 25, 1981, the Solemnity of the Annunciation of the Lord, the third year of the Pontificate.