"On the completion of the work which the Father gave the Son to do on earth (cf. Jn 17:4) the Holy Spirit was sent on the day of Pentecost to be the perennial agent of the Church's sanctification; in this way believers were to have access to the Father in one Spirit through Christ (cf. Eph 2:18). He is the Spirit of life or the spring of water welling up to eternal life (cf. Jn 4:14; 7:38-39). By him the Father gives life to men, who are dead because of sin, until he shall raise their mortal bodies in Christ (cf. Rom 8:10-11). The Spirit has his dwelling in the Church and in the hearts of the faithful as in a temple (cf. 1 Cor 3:16; 6:19); that is where he prays and bears witness to the fact of adoption (cf. Gal 4:6; Rom 8:15-16, 26). He guides the Church into all the truth (cf. Jn 16:13): he makes her one in fellowship and service; he fits her out with gifts of different kinds, hierarchical and charismatic, and makes his fruits her adornment (cf. Eph 4:11-12; 1 Cor 12:4; Gal 5:22). By the power of the Gospel he gives the Church youth and continual renewal, and he brings her safe to the consummation of union with her Bridegroom. For the Spirit and the Bride say to the Lord Jesus: 'come' (Rev 22:17)."
--Lumen Gentium, 4