The Holy Spirit and the Church (Catechism of the Catholic Church [CCC])
742 "Because you are sons, God has sent the Spirit of his Son into our hearts, crying, 'Abba! Father!"' (Gal 4:6).
743 From the beginning to the end of time, whenever God sends his Son, he always sends his Spirit: their mission is conjoined and inseparable.
744 In the fullness of time the Holy Spirit completes in Mary all the preparations for Christ's coming among the People of God. By the action of the Holy Spirit in her, the Father gives the world Emmanuel "God-with-us" (Mt 1:23).
745 The Son of God was consecrated as Christ (Messiah) by the anointing of the Holy Spirit at his Incarnation (cf. Ps 2:6-7).
746 By his Death and his Resurrection, Jesus is constituted in glory as Lord and Christ (cf. Acts 2:36). From his fullness, he poured out the Holy Spirit on the apostles and the Church.
747 The Holy Spirit, whom Christ the head pours out on his members, builds, animates, and sanctifies the Church. She is the sacrament of the Holy Trinity's communion with men.