Thomas Aquinas, Compendium of Theology

This, then, is the second of God's effects, namely, the government of things, and especially of rational creatures, to whom God gives grace and whose sins He forgives. This effect is touched on in the Creed. When we profess that the Holy Spirit is God, we imply that all things are ordained to the end of divine goodness, since it belongs to God to order His subjects to their end. And the words of the Creed which express our belief that the Holy Ghost is "the Life-giver," suggest that God moves all things. For, as the movement flowing from the soul to the body is the life of the body, so the movement whereby the universe is moved by God is, so to speak, a certain life of the universe.

Further, since the entire process of divine government is derived from the divine goodness, which is appropriated to the Holy Spirit, who proceeds as love, the effects of divine providence are fittingly thought of in connection with the person of the Holy Spirit.

As regards the effect of supernatural knowledge, which God produces in men through faith, the Creed proclaims: "I believe in . . . the Holy, Catholic Church"; for the Church is the congregation of the faithful. Concerning the grace which God communicates to men the Creed states: "I believe in . . . the communion of saints." And with respect to the remission of sin it says: "I believe in . . . the forgiveness of sins."