In fact, the paschal mystery — the passion, death and resurrection of Christ and his ascension into Heaven — finds its fulfillment in the powerful outpouring of the Holy Spirit on the Apostles gathered together with Mary, Mother of the Lord, and the other disciples. It was the “baptism” of the Church, baptism in the Holy Spirit (cf. Acts 1:5)… God’s voice divinized the human language of the Apostles who were enabled to proclaim the one divine Word in a “polyphonic” manner. The breath of the Holy Spirit fills the universe, generates faith, leads to truth, and predisposes people to unity…The Holy Spirit, “who is the Lord and Giver of life” — as we say in the Creed — is joined to the Father through the Son and completes the revelation of the Blessed Trinity. He comes from God like a breath from his mouth and has the power of sanctifying, abolishing divisions, dispelling the confusion due to sin. Incorporeal and immaterial, he lavishes divine goods upon living beings and sustains them so that they may act in conformity with the good. As an intelligible Light he gives meaning to prayer, vigor to the evangelizing mission, he makes the hearts of those who listen to the happy message burn and inspires Christian art and liturgical music.
Regina Caeli Address, June 12, 2011