1. We have often quoted the words of Jesus, who in his farewell discourse addressed to the apostles in the Upper Room promises the coming of the Holy Spirit as a new and definitive defender and consoler: "I will pray to the Father and he will give you another Paraclete to abide with you forever, the Spirit of truth, whom the world cannot receive, because it neither sees nor knows him" (Jn 14:16-17). That "farewell discourse", situated in the solemn account of the Last Supper (cf. Jn 13:2), is a source of prime importance for pneumatology, that is, for the theological discipline concerning the Holy Spirit. Jesus speaks of him as the Paraclete, who "proceeds" from the Father, and whom the Father will "send" to the apostles and the Church "in the name of the Son", when the Son himself "goes away", "at the price" of the departure accomplished through the sacrifice of the Cross.

We must take into consideration the fact that Jesus calls the Paraclete the "Spirit of Truth". Also at other times he called him this (cf. Jn 15:26; Jn 16:13).

2. Let us bear in mind that in the same "farewell discourse" Jesus, responding to a question from the apostle Thomas about his identity, asserts of himself: "I am the way, the truth and the life" (Jn 14:6). From this twofold reference to truth that Jesus makes to define both himself and the Holy Spirit, one deduces that if the Paraclete is called by him the "Spirit of truth", this means that the Holy Spirit is the one who, after Christ's departure, will maintain among the disciples the same truth, which he proclaimed and revealed and, indeed, which he himself is. The Paraclete, in fact, is the truth, as Christ is. John says this in his first letter: "It is the Holy Spirit who bears witness, because the Spirit is the truth" (John 5, 6). In the same letter, the Apostle also writes: "We are of God. He who knows God listens to us; he who is not of God does not listen to us. From this we distinguish the spirit of truth and the spirit of error ("spiritus erroris")" (Jn 4:6). The mission of the Son and that of the Holy Spirit meet, are connected and complement each other in the affirmation of truth and the victory over error. The fields of action in which they operate are the human spirit and world history. The distinction between truth and error is the first moment of this work.

3. Remaining in the truth and working in the truth is the essential problem for the apostles and disciples of Christ, both of the early times and of all the new generations of the Church throughout the centuries. From this point of view, the proclamation of the Spirit of truth is of key importance. Jesus says in the Upper Room: "Many things I have yet to say to you, but for the moment (yet) you are not able to bear the burden of them" (John 16: 12). Actually, Jesus' messianic mission lasted only a short time, too short to reveal to the disciples all the contents of Revelation. And not only was time short, but the preparation and intelligence of the listeners was also limited. Several times it is said that the apostles themselves "were astonished within themselves" (cf. Mk 6:52), and "did not understand" (cf. e.g. Mk 8:21), or understood Christ's words and works in a distorted way (cf. e.g. Mt 16:6-11).

Thus the Master's words are explained in all the fullness of their meaning: "When . . . the Spirit of truth will come, he will guide you into all truth" (Jn 16:13).

4. The first confirmation of this promise of Jesus will occur at Pentecost and in the days that follow, as the Acts of the Apostles attest. But the promise does not only concern the apostles and their immediate companions in evangelisation, but also future generations of Christ's disciples and confessors. For the Gospel is destined for all nations and the ever new generations, which will develop in the context of different cultures and the manifold progress of human civilisation. Looking across the whole range of history Jesus says: "The Spirit of truth who proceeds from the Father, he will bear witness to me". "He will 'bear witness', that is, he will show the true meaning of the Gospel within the Church, so that she may proclaim it authentically to the whole world. Always and everywhere, even in the interminable vicissitudes of things that change as they develop in the life of humanity, the "Spirit of truth" will guide the Church "into all truth" (John 16: 13).

5. The relationship between the Revelation communicated by the Holy Spirit and that of Jesus is very close. This is not a different, heterogeneous Revelation. This can be inferred from a detail of the language used by Jesus in his promise: "The Paraclete, the Holy Spirit, whom the Father will send in my name, he will teach you all things and bring to your remembrance all that I have said to you" (Jn 14:26). Remembering is the function of memory. By remembering, one returns to what has already been, to what has been said and done, thus renewing past things in the consciousness, and almost reviving them. Since it is especially the Holy Spirit who is the Spirit of a truth charged with divine power, his mission is not exhausted in remembering the past as such: by "remembering" the words, works and the entire salvific mystery of Christ, the Spirit of truth makes him continually present in the Church, ensures that he is ever more "present" in the community of salvation. Thanks to the action of the Holy Spirit, the Church not only remembers the truth, but abides and lives in the truth received from her Lord. This also fulfils Christ's words: "He (the Holy Spirit) will bear witness to me" (Jn 15:26). This witness of the Spirit of truth is thus identified with the ever-living presence of Christ, with the working power of the Gospel, with the increasing implementation of Redemption, with a continuous illustration of truth and virtue. In this way the Holy Spirit "guides" the Church "into all truth".

6. This truth is present, at least implicitly, in the Gospel. What the Holy Spirit will reveal has already been said by Christ. He himself reveals this when, speaking of the Holy Spirit, he emphasises that "he will not speak of himself, but will say whatever he has heard . . . He will glorify me, for he will take of mine and proclaim it to you" (John 16: 13-14). The Christ, glorified by the Spirit of truth, is first of all that same crucified Christ, stripped of everything and almost "annihilated" in his humanity for the redemption of the world. It was precisely by the power of the Holy Spirit that the "word of the Cross" had to be accepted by the disciples, to whom the Master himself had said: "For the moment (yet) you are not able to bear its burden" (Jn 16:12). There stood before those poor men the screen of the Cross. Deep action was needed to make their minds and hearts capable of discovering the "glory of redemption" that was accomplished in the Cross. Divine intervention was needed to convince and inwardly transform each one of them, in preparation, first of all, for the day of Pentecost, and then for the apostolic mission to the world. And Jesus warns them that the Holy Spirit "will glorify me, for he will take of mine and proclaim it to you". Only the Spirit, who, according to St Paul (1 Cor 2:10), "searches the depths of God", knows the mystery of the Son-Werbo in his filial relationship with the Father and in his redemptive relationship with men of all times. He alone, the Spirit of truth, can open human minds and hearts, making them capable of accepting the unfathomable mystery of God and His incarnate, crucified and risen Son, Jesus Christ the Lord.

7. Jesus says again: "The Spirit of truth . . . he will proclaim to you the things to come" (Jn 16:13). What does this prophetic and eschatological projection mean, by which Jesus places under the ray of the Holy Spirit the entire future of the Church, the entire historical journey that she is called to make over the centuries? It means a going forth to meet the glorious Christ, towards whom she is reaching out in the invocation raised by the Spirit: "Come, Lord Jesus!" (Rev 22:17. 20). The Holy Spirit leads the Church towards constant progress in the understanding of revealed truth. He watches over the pursuit of that truth, its preservation, its application to changing historical situations. He arouses and leads the development of everything that serves the knowledge and dissemination of this truth: in particular, the exegesis of Sacred Scripture and theological research, which can never be separated from the direction of the Spirit of truth nor from the Magisterium of the Church, in which the Spirit is always at work.

Everything takes place in faith and through faith, under the action of the Spirit, as is said in the encyclical Dominum et Vivificantem: "The Mysterium Christi in its totality demands faith, since it is this that appropriately introduces man into the reality of the revealed mystery. Leading to the whole truth is accomplished, therefore, in faith and through faith: which is the work of the Spirit of truth and is the fruit of His action in man. The Holy Spirit must be in this the supreme guide of man, the light of the human spirit. This applies to the apostles, eyewitnesses, who must now bring to all men the proclamation of what Christ 'did and taught' and, especially, of his Cross and Resurrection. In a more distant perspective, this is also true for all generations of the Master's disciples and confessors, since they will have to accept with faith and confess with frankness the mystery of God at work in human history, the revealed mystery that explains the definitive meaning of that history" (Dominum et Vivificantem, 6).

In this way the 'Spirit of truth' continually announces future things; He continually shows mankind this future of God, which is above and beyond all "temporal" futures: and thus fills the future of the world with eternal value. Thus the Spirit convinces man, making him realise that, with all that he is, and has, and does, he is called by God in Christ to salvation. Thus the "Paraclete", the Spirit of truth, is the true "Comforter" of man. Thus is the true Defender and Advocate. Thus he is the true Guarantor of the Gospel in history: under his influence the Good News is always "the same" and is always "new"; and in an ever new way he enlightens man's path in the perspective of heaven with "words of eternal life" (Jn 6:68).

[Pope John Paul II, General Audience 17 May 1989]