The Holy Spirit is the Soul of the Church.

Holy Gospel of Jesus Christ according to Saint John 15:26-27.16:1-4.

When the Advocate comes whom I will send you from the Father, the Spirit of truth that proceeds from the Father, he will testify to me. And you also testify, because you have been with me from the beginning. I have told you this so that you may not fall away. They will expel you from the synagogues; in fact, the hour is coming when everyone who kills you will think he is offering worship to God. They will do this because they have not known either the Father or me. I have told you this so that when their hour comes you may remember that I told you. "I did not tell you this from the beginning, because I was with you. Confraternity of Christian Doctrine, USCCB Commentary of the day : Paul VI, Pope from 1963-1978 Evangelii nuntiandi, ch. 7, §75

**“When the Advocate comes, the Spirit of truth, he will testify on my behalf” It is in the "consolation of the Holy Spirit" that the Church increases. The Holy Spirit is the Soul of the Church. It is He who explains to the faithful the deep meaning of the teaching of Jesus and of His mystery. It is the Holy Spirit who, today just as at the beginning of the Church, acts in every evangelizer who allows himself to be possessed and led by Him. The Holy Spirit places on his lips the words which he could not find by himself, and at the same time the Holy Spirit predisposes the soul of the hearer to be open and receptive to the Good News and to the kingdom being proclaimed.Techniques of evangelization are good, but even the most advanced ones could not replace the gentle action of the Spirit. The most perfect preparation of the evangelizer has no effect without the Holy Spirit. Without the Holy Spirit the most convincing dialectic has no power over the heart of man. Without Him the most highly developed schemas resting on a sociological or psychological basis are quickly seen to be quite valueless. We live in the Church at a privileged moment of the Spirit. Everywhere people are trying to know Him better, as the Scripture reveals Him. They are happy to place themselves under His inspiration. They are gathering about Him; they want to let themselves be led by Him. Now if the Spirit of God has a preeminent place in the whole life of the Church, it is in her evangelizing mission that He is most active. It is not by chance that the great inauguration of evangelization took place on the morning of Pentecost, under the inspiration of the Spirit.

It must be said that the Holy Spirit is the principal agent of evangelization: it is He who impels each individual to proclaim the Gospel, and it is He who in the depths of consciences causes the word of salvation to be accepted and understood. But it can equally be said that He is the goal of evangelization: He alone stirs up the new creation, the new humanity of which evangelization is to be the result, with that unity in variety which evangelization wishes to achieve within the Christian community. Through the Holy Spirit the Gospel penetrates to the heart of the world, for it is He who causes people to discern the signs of the times — signs willed by God — which evangelization reveals and puts to use within history.