The Council of Ephesus (431)
The Ninth Anathema: He Worked by His Own Spirit
If anyone says that the one Lord Jesus Christ was glorified by the Holy Spirit, so that he used through him a power not his own, and received from him power against unclean spirits and power to work miracles before people; and does not rather confess that it was his own Spirit through which he worked these divine signs: let him be anathema.
Nestorius’s ninth counter-anathema: If anyone says that the form of a servant is of the same nature as the Holy Spirit, and does not rather say that it owes its union with the Word, which has existed since the conception, to his mediation, by which it works miraculous healings among people and has the power to drive out demons: let him be anathema.
Petavius: The aim of this anathema is to show that the Word of God, when he took flesh, remaining what he was and lacking nothing that the Father has except only being the Father, had as his own the Holy Spirit, who is from him and abides in him in his very being. From this it follows that he worked his wonders and cast out demons through the Spirit as through a power and strength that was his own, not foreign to him or brought in from outside. He did not receive that Holy Spirit and his power as a kind of gift, the way the prophets had done before, or as his disciples did afterward. The Eastern bishops objected that Saint Cyril contradicts himself, for here he says that Christ did not work his wonders by the Holy Spirit, and in another place he openly confesses that he did work them so. But the whole point is what is meant by working through the Holy Spirit. The apostles worked miracles through the Holy Spirit, but as through a power outside themselves. Not so Christ. When Christ worked wonders through the Holy Spirit, he was working through a power that was his own, namely the third person of the Holy Trinity, from whom he never was and never could be separated, who always abides with him and the eternal Father in the divine unity. Western writers have always pointed to this anathema as showing that Saint Cyril recognized the eternal relation of the Holy Spirit as being from the Son.