Having proved above that the Spirit abides and speaks in the prophets, St. Ambrose infers that He knows all things which are of God, and therefore is One with the Father and the Son. This same point he establishes again from the fact that He possesses all that God possesses, namely, Godhead, knowledge of the heart, truth, a Name above every name, and power to raise the dead, as is proved from Ezekiel, and in this He is equal to the Son.
144. And so as the Father and the Son are One, because the Son has all things which the Father has, so too the Spirit is one with the Father and the Son, because He too knows all the things of God. For He did not obtain it by force, so that there should be any injury as of one who had suffered loss; He did not seize it, lest the loss should be his from whom it might seem to have been plundered. For neither did He seize it through need, nor through superiority of greater power did He take it by force, but He possesses it by unity of power. Therefore, if He works all these things, for one and the same Spirit works all, how is He not God Who has all things which God has?
145. Or let us consider what God may have which the Holy Spirit has not. God the Father has Godhead, and the Son, too, in Whom dwells the fullness of the Godhead, has it, and the Spirit has it, for it is written: “The Spirit of God is in my nostrils.”
146. God, again, searches the hearts and reins, for it is written: “God searches the hearts and reins.” The Son also has this power, Who said, “Why do you think evil in your hearts?” For Jesus knew their thoughts. And the Spirit has the same power, Who manifests to the prophets also the secrets of the hearts of others, as we said above: “for the secrets of his heart are made manifest.” And why do we wonder if He searches the hidden things of man Who searches even the deep things of God?
147. God has as an attribute that He is true for it is written: “Let God be true and every man a liar.” Does the Spirit lie Who is the Spirit of Truth? and Whom we have shown to be called the Truth, since John called Him too the Truth, as also the Son? And David says in the psalm: “Send out Your light and Your truth, they have led me and brought me to Your holy hill and to Your tabernacles.” If you consider that in this passage the Son is the light, then the Spirit is the Truth, or if you consider the Son to be the Truth, then the Spirit is the light.
148. God has a Name which is above every name, and has given a name to the Son, as we read that in the Name of Jesus knees should bow. Let us consider whether the Spirit has this Name. But it is written “Go, baptize the nations in the Name of the Father, and of the Son, and of the Holy Spirit.” He has, then, a Name above every name. What, therefore, the Father and the Son have, the Holy Spirit also has through the oneness of the Name of His nature.
149. It is a prerogative of God to raise the dead. “For as the Father raises the dead and quickens them, so the Son also quickens whom He will.” But the Spirit also (by Whom God raises) raises them, for it is written: “He shall quicken also your mortal bodies through His Spirit that dwells in you.” But that you may not think this a trivial grace, learn that the Spirit also raises, for the prophet Ezekiel says: “Come, O Spirit, and breathe upon these dead, and they shall live. And I prophesied as He commanded me, and the Spirit of life entered into them, and they lived, and stood up on their feet an exceeding great company.” And farther on God says: “You shall know that I am the Lord, when I shall open your graves, that I may bring My people out of their graves, and I will give you My Spirit, and you shall live.”
150. When He spoke of His Spirit, did He mention any other besides the Holy Spirit? For He would neither have spoken of His Spirit as produced by blowing, nor could this Spirit come from the four quarters of the world, for the blowing of these winds, which we experience, is partial, not universal; and this spirit by which we live is also individual, not universal. But it is the nature of the Holy Spirit to be both over all and in all. Therefore from the words of the prophet we may see how (the frame-work of the members long since fallen asunder being scattered) the bones may come together again to the form of a revived body, when the Spirit quickens them; and the ashes may come together on the limbs belonging to them, animated by a disposition to come together before being formed anew in the appearance of living.
151. Do we not in the likeness of what is done recognize the oneness of the divine power? The Spirit raises after the same manner as the Lord raised at the time of His own Passion, when suddenly in the twinkling of an eye the graves of the dead were opened, and the bodies living again arose from the tombs, and the smell of death being removed, and the scent of life restored, the ashes of those who were dead took again the likeness of the living.
152. So, then, the Spirit has that which Christ has, and therefore what God has, for all things which the Father has the Son also has, and therefore He said: “All things which the Father has are Mine.”
Source: On the Holy Spirit (New Advent)