1 It certainly was in the power of the apostles to declare that Christ descended upon Jesus, or that the so-called superior Saviour [came down] upon the dispensational one, or he who is from the invisible places upon him from the Demiurge; but they neither knew nor said anything of the kind: for, had they known it, they would have also certainly stated it. But what really was the case, that did they record, [namely,] that the Spirit of God as a dove descended upon Him; this Spirit, of whom it was declared by Isaiah, “And the Spirit of God shall rest upon Him,” as I have already said. And again: “The Spirit of the Lord is upon Me, because He has anointed Me.” That is the Spirit of whom the Lord declares, “For it is not you that speak, but the Spirit of your Father which speaks in you.” And again, giving to the disciples the power of regeneration into God, He said to them, “Go and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.” For [God] promised, that in the last times He would pour Him [the Spirit] upon [His] servants and handmaids, that they might prophesy; wherefore He did also descend upon the Son of God, made the Son of man, becoming accustomed in fellowship with Him to dwell in the human race, to rest with human beings, and to dwell in the workmanship of God, working the will of the Father in them, and renewing them from their old habits into the newness of Christ.
2. This Spirit did David ask for the human race, saying, “And establish me with Your all-governing Spirit;” who also, as Luke says, descended at the day of Pentecost upon the disciples after the Lord's ascension, having power to admit all nations to the entrance of life, and to the opening of the new covenant; from whence also, with one accord in all languages, they uttered praise to God, the Spirit bringing distant tribes to unity, and offering to the Father the first-fruits of all nations. Wherefore also the Lord promised to send the Comforter, who should join us to God. For as a compacted lump of dough cannot be formed of dry wheat without fluid matter, nor can a loaf possess unity, so, in like manner, neither could we, being many, be made one in Christ Jesus without the water from heaven. And as dry earth does not bring forth unless it receive moisture, in like manner we also, being originally a dry tree, could never have brought forth fruit unto life without the voluntary rain from above. For our bodies have received unity among themselves by means of that laver which leads to incorruption; but our souls, by means of the Spirit. Wherefore both are necessary, since both contribute towards the life of God, our Lord compassionating that erring Samaritan woman — who did not remain with one husband, but committed fornication by [contracting] many marriages— by pointing out, and promising to her living water, so that she should thirst no more, nor occupy herself in acquiring the refreshing water obtained by labour, having in herself water springing up to eternal life. The Lord, receiving this as a gift from His Father, does Himself also confer it upon those who are partakers of Himself, sending the Holy Spirit upon all the earth.
3. Gideon, that Israelite whom God chose, that he might save the people of Israel from the power of foreigners, foreseeing this gracious gift, changed his request, and prophesied that there would be dryness upon the fleece of wool (a type of the people), on which alone at first there had been dew; thus indicating that they should no longer have the Holy Spirit from God, as says Esaias, “I will also command the clouds, that they rain no rain upon it,” but that the dew, which is the Spirit of God, who descended upon the Lord, should be diffused throughout all the earth, “the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and piety, the spirit of the fear of God.” This Spirit, again, He did confer upon the Church, sending throughout all the world the Comforter from heaven, from whence also the Lord tells us that the devil, like lightning, was cast down. Wherefore we have need of the dew of God, that we be not consumed by fire, nor be rendered unfruitful, and that where we have an accuser there we may have also an Advocate, the Lord commending to the Holy Spirit His own man, who had fallen among thieves, whom He Himself compassionated, and bound up his wounds, giving two royal denaria; so that we, receiving by the Spirit the image and superscription of the Father and the Son, might cause the denarium entrusted to us to be fruitful, counting out the increase [thereof] to the Lord.
4. The Spirit, therefore, descending under the predestined dispensation, and the Son of God, the Only-begotten, who is also the Word of the Father, coming in the fullness of time, having become incarnate in man for the sake of man, and fulfilling all the conditions of human nature, our Lord Jesus Christ being one and the same, as He Himself the Lord does testify, as the apostles confess, and as the prophets announce—all the doctrines of these men who have invented putative Ogdoads and Tetrads, and imagined subdivisions [of the Lord's person], have been proved falsehoods. These men do, in fact, set the Spirit aside altogether; they understand that Christ was one and Jesus another; and they teach that there was not one Christ, but many. And if they speak of them as united, they do again separate them: for they show that one did indeed undergo sufferings, but that the other remained impassible; that the one truly did ascend to the Pleroma, but the other remained in the intermediate place; that the one does truly feast and revel in places invisible and above all name, but that the other is seated with the Demiurge, emptying him of power. It will therefore be incumbent upon you, and all others who give their attention to this writing, and are anxious about their own salvation, not readily to express acquiescence when they hear abroad the speeches of these men: for, speaking things resembling the [doctrine of the] faithful, as I have already observed, not only do they hold opinions which are different, but absolutely contrary, and in all points full of blasphemies, by which they destroy those persons who, by reason of the resemblance of the words, imbibe a poison which disagrees with their constitution, just as if one, giving lime mixed with water for milk, should mislead by the similitude of the colour; as a man superior to me has said, concerning all that in any way corrupt the things of God and adulterate the truth, “Lime is wickedly mixed with the milk of God.”
Source: Adversus haereses (New Advent)