1. The revelation of the Holy Spirit as a person distinct from the Father and the Son, foreshadowed in the Old Testament, becomes clear and explicit in the New.

It is true that the New Testament writings do not offer us systematic teaching on the Holy Spirit. However, by gathering the many statements found in the writings of Luke, Paid and John, it is possible to perceive the convergence of these three great currents of New Testament revelation concerning the Holy Spirit.

2. Compared to the other two Synoptic Gospels, the Evangelist Luke offers us a far more developed pneumatology.

In the Gospel he intends to show us that Jesus alone possesses the fullness of the Holy Spirit. Of course, the Spirit also comes upon Elizabeth, Zechariah, John the Baptist and especially Mary herself, but it is only Jesus, throughout his earthly life, who fully possesses God’s Spirit. He is conceived by the work of the Holy Spirit (cf. Lk 1:35). The Baptist will say of him: "baptize you with water; but he who is mightier than I is coming ... he will baptize you with the Holy Spirit and with fire" (Lk 3:16).

Before being baptized with the Holy Spirit and with fire, Jesus was baptized in the Jordan and "the Holy Spirit descended upon him in bodily form, as a dove" (Lk 3:22). Luke stresses that Jesus not only goes into the wilderness "led by the Spirit", but that he goes there "full of the Holy Spirit" (Lk 4: 1) and is victorious there over the tempter. He undertakes his mission "in the power of the Spirit" (Lk 4:14). In the synagogue at Nazareth, when he officially begins his mission, Jesus applies to himself the prophecy of the book of Isaiah (cf. 61:12): "The Spirit of the Lord is upon me, because he has anointed me to preach good news to the poor" (Lk 4:18). All of Jesus’ evangelizing activity is thus guided by the Spirit.

This same Spirit will sustain the Church’s evangelizing mission, as the Risen One had promised his disciples: "Behold, I send the promise of my Father upon you; but stay in the city, until you are clothed with power from on high" (Lk 24:49). According to the book of Acts, the promise is fulfilled on the day of Pentecost: "And they were all filled with the Holy Spirit and began to speak in other tongues, as the Spirit gave them utterance" (Acts 2:4). Joel’s prophecy is thus realized: "In the last days it shall be, God declares, that I will pour out my Spirit upon all flesh, and your sons and your daughters shall prophesy" (Acts 2:17). Luke sees the Apostles as representing the People of God of the last days and rightly emphasizes that this Spirit of prophecy involves the whole People of God.

3. St Paid in turn highlights the aspect of renewal and the eschatological dimension of the Spirit’s work: the Spirit is seen as the source of the new and eternal life that Jesus communicates to his Church.

In the First Letter to the Corinthians we read that Christ, the new Adam, by virtue of the Resurrection, became "a life-giving spirit" (1 Cor 15:45): he was transformed by the vital power of God’s Spirit so as to become, in turn, a principle of new life for believers. Christ communicates this life precisely through the outpouring of the Holy Spirit.

Believers no longer five as slaves under the law, but as sons, because in their hearts they have received the Spirit of the Son and can cry out: "Abba, Father!" (cf. Gal 4:5-7; Rom 8:14-16). It is a life "in Christ", that is, a life of belonging exclusively to him and of incorporation into the Church: "For by one Spirit we were all baptized into one body" (cf. 1 Cor 12:13). The Holy Spirit gives rise to faith (1 Cor 12:3), pours love into our hearts (cf. Rom 5:5) and guides the prayer of Christians (cf. Rom 8:26).

As the principle of a new existence, the Holy Spirit also produces a new and active dynamism in the believer: "If we live by the Spirit, let us also walk by the Spirit" (Gal 5:25). This new life is opposed to that of the "flesh", whose desires displease God and enclose the person in the suffocating prison of an ego turned in on itself (cf. Rom 8:5-9). Instead, by opening himself to the Holy Spirit, the Christian can taste the fruits of the Spirit: love, joy, peace, patience, kindness, goodness, faithfulness, etc. (cf. Gal 5:16-24).

According to Paul, however, what we now possess is only a "down payment" or the first fruits of the Spirit (cf. Rom 8:23; cf. also 2 Cor 5:5). In the final resurrection, the Spirit will complete his masterpiece by bringing about, for believers, the full "spiritualization" of their bodies (cf. I Cor 15:43-44) and in some way involving the whole universe in salvation as well (cf. Rom 8:20-22).

4. In the Johannine perspective, the Holy Spirit is above all the Spirit of truth, the Paraclete.

Jesus announces the gift of the Spirit as he completes his earthly work: ‘When the Paraclete comes, the Spirit of truth who comes from the Father – and whom I myself will send from the Father – he will bear witness on my behalf. You must bear witness as well, for you have been with me from the beginning" (Jn 15:26ff.). In further explaining the Spirit’s role, Jesus adds: "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. He will glorify me, for he will take what is mine and declare it to you" (Jn 16:13-14). Thus, the Spirit will not bring a new revelation, but will guide the faithful to an interiorization and deeper penetration of the truth revealed by Jesus.

What does it mean to call the Spirit of truth the Paraclete? Bearing in mind the Johannine perspective which views Jesus’ trial as one that continues in the disciples who will be persecuted because of his name, the Paraclete is the one who defends the cause of Jesus, convincing the world "of sin, of righteousness and of judgement" (Jn 16:7f.). The fundamental sin which the Paraclete will make known is not to have believed in Christ. The justice he indicates is that which the Father gave his crucified Son by glorifying him in the Resurrection and Ascension into heaven. The judgement, in this context, consists in revealing the sin of those who, dominated by Satan, the prince of this world (cf. Jn 16:11), rejected Christ (cf. Dominum et Vivificantem, n. 27). With his inner assistance, the Holy Spirit is therefore the defender and supporter of Christ’s cause, the One who leads the minds and hearts of disciples to full acceptance of the ‘truth’ of Jesus.