Now I just have to figure out what it all means....
For those of you bored and surfing, feel free to compare this passage from Augustine's De Trinitate, XV, 46 (c. 420AD) to what I just found in Hilary of Poitiers' De Trinitate, XI, 18-20 (c. 360).
That is why the Lord Jesus himself not only gave the Holy Spirit as God but also received him as man, and for that reason he was called full of grace. It is written of him more openly in the Acts of the Apostles, that God anointed him with the Holy Spirit, not of course with a visible oil but with the gift of grace which is signified by the chrism the Church anoints the baptized with. Nor, to be sure, was Christ only anointed with the Holy Spirit when the dove came down upon him at his baptism; what he was doing then was graciously prefiguring his body, that is his Church, in which it is particularly those who have just been baptized that receive the Holy Spirit. But we must realize that he was anointed with this mystical and invisible anointing when the Word of God became flesh, that is when a human nature without any antecedent merits of good works was coupled to the Word of God in the virgin's womb so as to become one person with him. This is why we confess that he was born of the Holy Spirit and the virgin Mary. It would be the height of absurdity to believe that he only received the Holy Spirit when he was already thirty years old--that was the age at which he was baptized by John; no, we must believe that just as he came to that baptism without any sin, so he came to it not without the Holy Spirit.
Hilary of Poitiers:
(18) The times or the ages do not cause a difference in the Spirit, so that there is not the same Christ Himself in the body who dwelt in the Prophets by the Spirit. When he declares through the mouth of patriarch David: ‘God, thy God, hath anointed thee with the oil of gladness above thy fellows,’ He did not say anything different according to the mystery than He said according to the dispensation of the body which He assumed. He who now confides to His brethren that their Father is His Father and their God His God, then declared that He was also anointed by His God above His fellows, so that, while there is no fellowship with the only-begotten Christ the Word of God, we realize that there is a fellowship with Him by that assumption in which He is flesh. That anointing did not procure any advantage for that blessed and incorrupt birth that abides in the nature of God, but for the mystery of the body and for the sanctification of the manhood which He took upon Himself, as the Apostle Peter testifies when he said: ‘For of a truth there assembled together in this city against thy holy Son Jesus, whom thou hast anointed.’ And again: “You know what took place throughout Judea; for he began in Galilee after the baptism preached by John: how God anointed Jesus of Nazareth with the Holy Spirit and with power.’ Jesus, therefore, is anointed in the mystery of the flesh that was born again. And there is no difficulty in regard to the manner in which He was anointed by the Spirit and by the power of God, since at that moment when He comes up from Jordan the voice of God the Father is heard: ‘Thou art my Son, this day have I begotten thee,’ in order that the anointing of the spiritual power might be recognized through this testimony of the flesh that was sanctified in Him.
(19) Moreover, since God the Word was in the beginning with God, the anointing rejects any cause for or any description of His nature, about which nothing else is made known than that it was in the beginning. And certainly it was not necessary for God, who is the Spirit and the power of God, to be anointed by the Spirit and the power of God. Hence, God is anointed by His God above His fellows. And if many were anointed according to the Law before the bestowal of the flesh, then Christ, who is now anointed above His fellows, is later in time, although He is preferred before all of His companions who were anointed. Finally, that prophetic utterance revealed this later anointing when it declared: ‘Thou hast loved justice and hated iniquity: therefore God, thy God, hath anointed thee with the oil of gladness above thy fellows.’
A consequent and later cause is never made retroactive so that it becomes first, for to merit anything follows upon the existence of Him who is capable of meriting. To merit belongs to Him who is the cause of acquiring merit for Himself. If, therefore, we attribute the anointing to the birth of the only-begotten God, and this anointing has been granted in recognition of His love for justice and His hatred of iniquity, then it is to be understood that the only-begotten God was not born, but was brought forth by the anointing and now He will be made perfect as God through an increase and gain, since He was not born as God but was anointed into God because of His merits, and now He will be the God Christ as the result of a cause and the cause of all things will not be through the God Christ. What, then, is the meaning of the Apostle’s words: ‘All things through him and unto him, and he is before all, and in him all things hold together’? God the Lord Jesus Christ is not God because of some things or through some things, but was born as God. And He who is God by birth did not develop into God after His birth through some other cause, but because He was born He is nothing else by His birth than what God is. If He is anointed as the result of a cause, then the benefit of the anointing does not refer to that which does not need to grow but to that which needs the benefit of the anointing through an increase of the mystery, that is to say, through the anointing our man Christ appears as one sanctified. IF in the present instance, therefore, the dispensation of the slave is also pointed out by the Prophet because of which He is anointed by His God above His fellows, and accordingly He is anointed because He loved justice and hated iniquity, why will not the Propet’s words refer to that nature of Christ which we share with Him by His assumption of the flesh, since the Spirit of prophecy has exercised particular care in this way, that, while God is anointed by His God, He is His God in the dispensation of the anointing and He is God in the nature? Consequently, God is anointed, but I ask the question whether the Word that was in the beginning with God was anointed? By no means! The anointing is later than God. Since the birth of the Word was not anointed, because it was in the beginning with God, then that must have been anointed in God which comes afterwards in the dispensation, in so far as He is God. And since God is anointed by His God, then everything pertaining to a slave that He received in the mystery of the flesh is anointed.
(20) Let no one, therefore, desecrate the mystery of godliness, that was made known in the flesh, by a godless interpretation, and let no one place himself on an equality with the Only-begotten in the substance of the Godhead. Let Him be a brother to and sharer with us in so far as the Word made flesh dwelt among us, and in so far as the man Jesus Christ is the mediator of God and man. Let us as slaves have a common Father and a common God, and let Him be anointed above His fellows in that nature in which His fellows were anointed, even though He was anointed with a special privilege. In the mystery of the mediator let Him be a true man as well as the true God, the God Himself from God, who has a common Father and God with us in that fellowship by which He is our brother.