The Holy Spirit
This Holy Spirit the Lord Christ calls at one time “the Paraclete,” at another pronounces to be the “Spirit of truth.” And He is not new in the Gospel, nor yet even newly given; … Assuredly in the Spirit there are different kinds of offices, because in the times there is a different order of occasions; and yet, on this account, He who discharges these offices is not different, nor is He another in so acting, but He is one and the same, … the Apostle Paul says, “Having the same Spirit; as it is written, I believed, and therefore have I spoken; we also believe, and therefore speak.” He is therefore one and the same Spirit who was in the prophets and apostles, except that in the former He was occasional, in the latter always … For, said He, “I will pray the Father, and He will give you another Advocate, that He may be with you for ever, even the Spirit of truth.” And, “When He, the Advocate, shall come, whom I shall send unto you from my Father, the Spirit of truth who proceedeth from my Father.”
For this is He who strengthened their hearts and minds, who marked out the Gospel sacraments, who was in them the enlightener of divine things; and they being strengthened, feared, for the sake of the Lord’s name, neither dungeons nor chains, nay, even trod under foot the very powers of the world and its tortures, since they were henceforth armed and strengthened by the same Spirit, having in themselves the gifts which this same Spirit distributes, and appropriates to the Church, the spouse of Christ, as her ornaments. This is He who places prophets in the Church, instructs teachers, directs tongues, gives powers and healings, does wonderful works, offers discrimination of spirits, affords powers of government, suggests counsels, and orders and arranges whatever other gifts there are of charismata ; and thus make the Lord’s Church everywhere, and in all, perfected and completed.
This is He who, after the manner of a dove, when our Lord was baptized, came and abode upon Him, dwelling in Christ full and entire, and not maimed in any measure or portion; but with His whole overflow copiously distributed and sent forth, so that from Him others might receive some enjoyment of His graces: the source of the entire Holy Spirit remaining in Christ. …For truly Isaiah, prophesying this, said: “And the Spirit of wisdom and understanding shall rest upon Him, the Spirit of counsel and might, the Spirit of knowledge and piety; and the Spirit of the fear of the Lord shall fill Him.” This self-same thing also he said in the person of the Lord Himself, in another place, “The Spirit of the Lord is upon me; because He has anointed me, He has sent me to preach the Gospel to the poor.” …
He it is who effects with water the second birth as a certain seed of divine generation, and a consecration of a heavenly nativity, the pledge of a promised inheritance, and as it were a kind of handwriting of eternal salvation; who can make us God’s temple, and fit us for His house; who solicits the divine hearing for us with groanings that cannot be uttered; filling the offices of advocacy, and manifesting the duties of our defence,—an inhabitant given for our bodies and an effector of their holiness. Who, working in us for eternity, can also produce our bodies at the resurrection of immortality, accustoming them to be associated in Himself with heavenly power, and to be allied with the divine eternity of the Holy Spirit. For our bodies are both trained in Him and by Him to advance to immortality, by learning to govern themselves with moderation according to His decrees.
For this is He who “desireth against the flesh,” because “the flesh resisteth against the Spirit.” This is He who restrains insatiable desires, controls immoderate lusts, quenches unlawful fires, conquers reckless impulses, repels drunkenness, checks avarice, drives away luxurious revellings, links love, binds together affections, keeps down sects, orders the rule of truth, overcomes heretics, turns out the wicked, guards the Gospel. Of this says the same apostle: “We have not received the spirit of the world, but the Spirit which is of God.” … Of Him also he tells: “Now the Spirit speaketh plainly, that in the last times some shall depart from the faith, giving heed to seducing spirits, doctrines of demons, who speak lies in hypocrisy, having their conscience cauterized.” Established in this Spirit, “none ever calleth Jesus anathema;” no one has ever denied Christ to be the Son of God, or has rejected God the Creator; no one utters any words of his own contrary to the Scriptures; no one ordains other and sacrilegious decrees; no one draws up different laws. Whosoever shall blaspheme against Him, “hath not forgiveness, not only in this world, but also not in the world to come.
This is He who in the apostles gives testimony to Christ; in the martyrs shows forth the constant faithfulness of their religion; in virgins restrains the admirable continency of their sealed chastity; in others, guards the laws of the Lord’s doctrine incorrupt and uncontaminated; destroys heretics, corrects the perverse, condemns infidels, makes known pretenders; moreover, rebukes the wicked, keeps the Church uncorrupt and inviolate, in the sanctity of a perpetual virginity and truth.
— On the Trinity XXIX