CCC 798 The Holy Spirit is “the principle of every vital and truly saving action in each part of the Body.”1 He works in many ways to build up the whole Body in charity:2 by God’s Word “which is able to build you up”;3 by Baptism, through which he forms Christ’s Body;4 by the sacraments, which give growth and healing to Christ’s members; by “the grace of the apostles, which holds first place among his gifts”;5 by the virtues, which make us act according to what is good; finally, by the many special graces (called “charisms”), by which he makes the faithful “fit and ready to undertake various tasks and offices for the renewal and building up of the Church.”6

1 Pius XII, encyclical, Mystici Corporis: DS 3808.
2 Cf. Eph 4:16.
3 Acts 20:32.
4 Cf. 1 Cor 12:13.
5 LG 7 # 2.
6 LG 12 # 2; cf. AA 3.