685 To believe in the Holy Spirit is to profess that the Holy Spirit is one of the persons of the Holy Trinity, consubstantial with the Father and the Son: “with the Father and the Son he is worshipped and glorified.” For this reason, the divine mystery of the Holy Spirit was already treated in the context of Trinitarian “theology.” Here, however, we have to do with the Holy Spirit only in the divine “economy.”
686 The Holy Spirit is at work with the Father and the Son from the beginning to the completion of the plan for our salvation. But in these “end times,” ushered in by the Son’s redeeming Incarnation, the Spirit is revealed and given, recognized and welcomed as a person. Now can this divine plan, accomplished in Christ, the firstborn and head of the new creation, be embodied in mankind by the outpouring of the Spirit: as the Church, the communion of saints, the forgiveness of sins, the resurrection of the body, and the life everlasting.
687 “No one comprehends the thoughts of God except the Spirit of God.” Now God’s Spirit, who reveals God, makes known to us Christ, his Word, his living Utterance, but the Spirit does not speak of himself. The Spirit who “has spoken through the prophets” makes us hear the Father’s Word, but we do not hear the Spirit himself. We know him only in the movement by which he reveals the Word to us and disposes us to welcome him in faith. The Spirit of truth who “unveils” Christ to us “will not speak on his own.” Such properly divine self–effacement explains why “the world cannot receive [him], because it neither sees him nor knows him,” while those who believe in Christ know the Spirit because he dwells with them.
688 The Church, a communion living in the faith of the apostles which she transmits, is the place where we know the Holy Spirit:
— in the Scriptures he inspired;
— in the Tradition, to which the Church Fathers are always timely witnesses;
— in the Church’s Magisterium, which he assists;
— in the sacramental liturgy, through its words and symbols, in which the Holy Spirit puts us into communion with Christ;
— in prayer, wherein he intercedes for us;
— in the charisms and ministries by which the Church is built up;
— in the signs of apostolic and missionary life;
— in the witness of saints through whom he manifests his holiness and continues the work of salvation.
 1 Cor 2:11
 Jn 16:13
 Jn 14:17
Excerpts from the English translation of the Catechism of the Catholic Church for use in the United States of America Copyright © 1994, United States Catholic Conference, Inc. – Libreria Editrice Vaticana. Used with Permission.