1. The Holy Spirit
In Sacred Scripture, the Holy Spirit is called by various names: Gift, Lord, Spirit of God, Spirit of Truth, and Paraclete, among others. Each of these names tells us something about the Third Person of the Holy Trinity. He is “Gift” because the Father and the Son give Him to us. The Spirit has come to dwell in our hearts (cf. Gal 4:6), to remain with us forever. Moreover, from Him come all graces and gifts, the greatest of which is eternal life with the other divine Persons. In Him we have access to the Father through the Son.
The Spirit is “Lord” and “Spirit of God,” which are names attributed to God alone in Holy Scripture, because He is God with the Father and the Son. He is “Spirit of Truth” because He teaches us all that Christ has revealed to us, because He guides and sustains the Church in the truth. He is the “other” Paraclete (Comforter, Advocate) promised by Christ, who is the first Paraclete. The Greek text says “another” Paraclete and not a “distinct” Paraclete in order to point to the communion and continuity between Christ and the Spirit.
In the Nicene-Constantinopolitan Creed we pray: “I believe in the Holy Spirit, the Lord, the giver of life, who proceeds from the Father and the Son, who with the Father and the Son is adored and glorified, who has spoken through the prophets.” In this sentence the Fathers of the Council of Constantinople (381) wanted to include some of the biblical expressions by which the Spirit is called. In saying He is the “giver of life” they meant God’s gift of divine life to us. Since he is Lord and giver of life, he is God and receives the same worship as the other two divine Persons. At the end of the sentence reference is made to the mission of the Spirit: He spoke through the prophets. The prophets are those who spoke in the name of God inspired by the Spirit. The revelatory work of the Spirit in the prophecies of the Old Testament finds its fullness in the mystery of Jesus Christ, the definitive Word of God.
“There are many symbols of the Holy Spirit: living water which springs from the wounded Heart of Christ and which quenches the thirst of the baptized; anointing with oil, which is the sacramental sign of Confirmation; fire which transforms what it touches; the cloud, dark or luminous, in which the divine glory is revealed; the imposition of hands by which the Holy Spirit is given; the dove which descended on Christ at his baptism and remained with him.”
2. Sending of the Holy Spirit
The Third Person of the Blessed Trinity cooperates with the Father and the Son from the beginning of the divine Plan for our salvation and until its consummation. But in the “last times” – inaugurated with the redemptive Incarnation of the Son – the Spirit was revealed and given to us, recognised and accepted as a Person. By the work of the Spirit, the Son of God took flesh in the womb of the Virgin Mary. The Spirit anointed Him from the first moment; that is why Jesus is the Messiah from the beginning of his humanity (cf. Lk 1:35). Jesus “revealed the Spirit in his teaching, fulfilled the promises made to the Fathers, and bestowed him upon the Church at its birth when he breathed on the apostles after the Resurrection.” At Pentecost the Spirit was sent to remain from then on in the Church, Christ’s Mystical Body, vivifying and guiding her with his gifts and his presence. He dwells in her as in the Incarnate Word. This is why the Church is also said to be the Temple of the Holy Spirit.
On the day of Pentecost the Spirit descended upon the Apostles and the first disciples, showing by outward signs his vivifying action on the Church founded by Christ. “The mission of Christ and of the Spirit became the mission of the Church, which is sent to proclaim and spread the mystery of the communion of the Holy Trinity.” The Spirit brings the world into the “last times,” the time of the Church.
The dwelling of the Holy Spirit in the Church ensures that everything Christ said and taught when He lived on earth until his Ascension is always kept alive and without loss. Moreover, through the celebration and administration of the sacraments, the Spirit sanctifies the Church and the faithful, so that she always continues to lead souls to God.
“In the indivisible Trinity, the Son and the Spirit are distinct but inseparable. From the very beginning until the end of time, when the Father sends his Son he also sends his Spirit who unites us to Christ in faith so that as adopted sons we can call God ‘Father’ (Rom 8:15). The Spirit is invisible but we know him through his actions, when he reveals the Word to us and when he acts in the Church.”
“The solemn coming of the Holy Spirit on Pentecost was not an isolated event. There is hardly a page in the Acts of the Apostles where we fail to read about him and the action by which he guides, directs and enlivens the life and work of the early Christian community . . . This profound reality which we see in the texts of Holy Scripture is not a remembrance from the past, from some golden age of the Church which has since been buried in history. Despite the weaknesses and the sins of every one of us, it is the reality of today's Church and the Church of all time.”
3. His action in the Church
The Holy Spirit always acts with Christ, from Christ, and conforms Christians to Christ. His action takes place in the Church through the sacraments. Through them Christ communicates his Spirit to the members of his Body, and offers them God’s grace, which brings forth the fruits of a new life, lived in accord with the Spirit. The Holy Spirit also acts by giving special graces to some Christians for the good of the whole Church, and is the Teacher who reminds all Christians of what Christ has revealed (cf. Jn 14:25ff.). Christ and the Spirit are “the two hands of God,” the two missions from which the Church has come forth (Saint Irenaeus of Lyons).
“The Spirit builds, animates and sanctifies the Church. As the Spirit of Love, he restores to the baptized the divine likeness that was lost through sin and causes them to live in Christ the very life of the Holy Trinity. He sends them forth to bear witness to the Truth of Christ and he organizes them in their respective functions so that all might bear ‘the fruit of the Spirit’ (Gal 5:22).”
When we say in the Creed that “I believe in the Holy Spirit; the Holy Catholic Church,” we are affirming that we believe in the Holy Spirit who is at work in the Church, sanctifying her, building her up according to the measure of Christ, encouraging her to carry out the mission entrusted to her. Although the literal expression in the vernacular seems to affirm that the act of faith is directed towards the Church, this is not the case in the Latin language. The act of faith is directed towards God and not towards the works of God. The Church is a work of God, and in the Creed we claim to believe that she is a work of God.
We often say that the Holy Spirit is like the soul of the Church because He performs in it some of the functions that the soul performs in the body. He vivifies the Church, impels it to carry out its mission, unifies it in love. But the relationship of the Holy Spirit with the Church is not the same as that between the human soul and body, which form one person. That is why we do not say that the Church is the personification of the Spirit or an incarnation of the Spirit.
The action of the Holy Spirit in the Church is also seen in his continuing influence on the souls of all Christians. Indeed, in addition to his action in the sacraments, the Spirit makes us grow in Christ, until we reach the stature of the perfect man. He is the interior teacher who speaks in our heart, who reveals the mysteries of God, who helps us discern what is pleasing to God, his divine and loving Will for each one of us. The Spirit teaches us to turn to God, to speak to Him (cf. Rom 8:26), and helps us to evaluate everything with faith.
This gift of the Spirit helps us to perceive the true value of things, events, people, the inner movements of the soul, evaluating them according to whether they bring us closer to God or turn us away from Him. It also helps us to discover how we can direct them to the perfection to which they are called, thus helping us to collaborate in the building up of God’s kingdom.
The Holy Spirit’s action in the Church is therefore quite varied. He acts in the hierarchy, in the sacraments, through the non-sacramental gifts and within the heart of each Christian, reaching into the innermost recesses of the body of the Church. This action is aimed at unifying all men and women with Christ, thus uniting all humanity and bringing creation to the fullness to which God has destined it (cf. Rom 8:19-22). The Church prolongs the mission of Christ in history and makes present the two divine missions.
Thus we see why the Church is the “temple of the Holy Spirit.” He lives in the body of the Church and builds it up in charity with the Word of God, with the sacraments, with the virtues and charisms. Since the true temple of the Holy Spirit was Christ (cf. Jn 2:19-22), this image also shows that every Christian is Church and temple of the Holy Spirit. “Charisms are special gifts of the Holy Spirit which are bestowed on individuals for the good of others, the needs of the world, and in particular for the building up of the Church. The discernment of charisms is the responsibility of the Magisterium.”
Catechism of the Catholic Church, 683-701; 731-741.
Compendium of the Catechism of the Catholic Church, 136-146.
Saint John Paul II, Catechesis on the Holy Spirit (August-December 1989).
Pope Francis, General Audience, 17 March 2021.
 Compendium of the Catechism of the Catholic Church, 139, hereafter Compendium.
 Cf. Catechism of the Catholic Church, 686, hereafter Catechism.
 Compendium, 143.
 Compendium, 144.
 Compendium, 137.
 Saint Josemaría, Christ Is Passing By, 127ff.
 Compendium, 145.
 Cf. Catechism, 750.
 “When you call upon God the Father, therefore, remember that it was the Spirit who, in moving your soul, gave you this prayer. If the Holy Spirit were not present, there would be no word of wisdom or knowledge in the Church, for it is written, ‘The word of wisdom is given by the Spirit' (1 Cor 12:8).... If the Holy Spirit were not present, the Church would not exist. But if the Church exists, it is certain that the Holy Spirit is present” Saint John Chrysostom, Sermones panegyrici in solemnitates D. Iesu Christi, hom. 1, De Sancta Pentecostes, 3-4 (PG 50,457).
 Compendium, 160.