When the time for Jesus to leave this world had almost come, he told the Apostles of "another Counselor"(Jn16:14). The evangelist John, who was present, writes that, during the Last Supper before the day of his Passion and Death, Jesus addressed the Apostles with these words: "Whatever you ask in my name, I will do it, that the Father may be glorified in the Son.... I will pray the Father, and he will give you another Counselor, to be with you forever, even the Spirit of truth" (Jn 14:13, 16f).
It is precisely this Spirit of truth whom Jesus calls the Paraclete-and parakletos means "counselor," and also "intercessor," or "advocate." And he says that the Paraclete is "another" Counselor, the second one, since he, Jesus himself, is the first Counselor, (Cf. 1 Jn 2:1) being the first bearer and giver of the Good News. The Holy Spirit comes after him and because of him, in order to continue in the world, through the Church, the work of the Good News of salvation. Concerning this continuation of his own work by the Holy Spirit Jesus speaks more than once during the same farewell discourse, preparing the Apostles gathered in the Upper Room for his departure, namely for his Passion and Death on the Cross.
The words to which we will make reference here are found in the Gospel of John. Each one adds a new element to that prediction and promise. And at the same time they are intimately interwoven, not only from the viewpoint of the events themselves but also from the viewpoint of the mystery of the Father, Son and Holy Spirit, which perhaps in no passage of Sacred Scripture finds so emphatic an expression as here.
A little while after the prediction just mentioned Jesus adds: "But the Counselor, 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). The Holy Spirit will be the Counselor of the Apostles and the Church, always present in their midst—even though invisible—as the teacher of the same Good News that Christ proclaimed. The words "he will teach" and "bring to remembrance" mean not only that he, in his own particular way, will continue to inspire the spreading of the Gospel of salvation but also that he will help people to understand the correct meaning of the content of Christ's message; they mean that he will ensure continuity and identity of understanding in the midst of changing conditions and circumstances. The Holy Spirit, then, will ensure that in the Church there will always continue the same truth which the Apostles heard from their Master.
In transmitting the Good News, the Apostles will be in a special way associated with the Holy Spirit. This is how Jesus goes on: "When the Counselor comes, whom I shall send to you from the Father, even the Spirit of truth, who proceeds from the Father, he will bear witness to me; and you also are witnesses, because you have been with me from the beginning" (Jn 15:26f).
Apostles were the direct eyewitnesses. They "have heard" and "have seen with their own eyes," "have looked upon" and even "touched with their hands" Christ, as the evangelist John says in another passage (Cf. 1 Jn 1:1-3; 4:14). This human, first-hand and "historical" witness to Christ is linked to the witness of the Holy Spirit: "He will bear witness to me." In the witness of the Spirit of truth, the human testimony of the Apostles will find its strongest support. And subsequently it will also find therein the hidden foundation of its continuation among the generations of Christ's disciples and believers who succeed one another down through the ages.
The supreme and most complete revelation of God to humanity is Jesus Christ himself, and the witness of the Spirit inspires, guarantees and convalidates the faithful transmission of this revelation in the preaching and writing of the Apostles (Divine Revelation, Dei Verbum, nn. 11, 12), while the witness of the Apostles ensures its human expression in the Church and in the history of humanity.
This is also seen from the strict correlation of content and intention with the just-mentioned prediction and promise, a correlation found in the next words of the text of John: "I have yet many things to say to you, but you cannot bear them now. When the Spirit of truth comes, he will guide you into all the truth; for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come" (Jn 16:12f).
In his previous words Jesus presents the; Counselor, the Spirit of truth, as the one who "will teach" and "bring to remembrance," as the one who "will bear witness" to him. Now he says: "He will guide you into all the truth." This "guiding into all the truth," referring to what the Apostles "cannot bear now," is necessarily connected with Christ's self-emptying through his Passion and Death on the Cross, which, when he spoke these words, was just about to happen.
Later however it becomes clear that this "guiding into all the truth" is connected not only with the scandal of the Cross, but also with everything that Christ "did and taught" (Acts 1:1). For the mystery of Christ taken as a whole demands faith, since it is faith that adequately introduces man into the reality of the revealed mystery. The "guiding into all the truth" is therefore achieved in faith and through faith: and this is the work of the Spirit of truth and the result of his action in man. Here the Holy Spirit is to be man's supreme guide and the light of the human spirit. This holds true for the Apostles, the eyewitnesses, who must now bring to all people the proclamation of what Christ did and taught, and especially the proclamation of his Cross and Resurrection. Taking a longer view, this also holds true for all the generations of disciples and confessors of the Master. Since they will have to accept with faith and confess with candor the mystery of God at work in human history, the revealed mystery which explains the definitive meaning of that history.