“In the outpouring of supernatural, filial, divine love, of caritas into our hearts, the interior outpouring of the love between the Father and the Son that is consummated in the Holy Spirit is continued because it is reproduced. So we can say not only that the love is given to us and is poured out upon us, but that the Holy Spirit Himself is given to us and poured out upon us in this love. We should do even better to say that the habit and act of charity, poured forth by the Holy Spirit, come into our heart by the very fact that He Himself, the torrent of divine love, is given and drawn to our soul.
Similarly in the conferring of supernatural divine light and the reflection of the divine nature upon our soul, in the impress of the supernatural likeness of God, the eternal splendor of the Father is irradiated over us, and His consubstantial image, the Son of God, is imprinted in our soul and is reborn in us by an imitation and extension of the eternal production. Thus God’s Son Himself in His divine and hypostatic character is lodge in the creature as the seal of the creature’s likeness to God. By the impress of this seal the creature is made conformable to the Son Himself, and by fellowship with the Son he receives the dignity and glory of the children of God.
The application to the creature of the divine love-flame flaring up in the Holy Spirit by the enkindling of a similar flame, and the reflection upon the creature of the divine glory shining in the Son by the irradiation of a similar splendor: these two images give us a striking illustration of the two divine missions as prolongations of the eternal processions and their entrance into the creature. These images become still more striking if we combine them with the image of the stamp of the seal imprinted by God upon the soul in the spiritual kiss wherein He so pours forth the light of His countenance and the sigh of His heart that the soul is illuminated and transfigured by His light, and inflamed and animated by His breath.
In the case of the Holy Spirit especially the outer procession as a prolongation of the inner is most fittingly expressed by saying that the Father and the Son breathe Him into the creature. This is the exalted sense in which the Fathers expound the words of Genesis: ‘And the Lord God...breathed into his face the breath of life.’
The statement just made would suffice in itself to enable us to perceive a true mission of the divine persons (Son and Holy Spirit) in the communication of grace. In this communication the Son and the Holy Spirit, as distinct from the Father and from each other, are present in the creature by virtue of a defining image impressed by each of them, an image which is so vivid and perfect that it infinitely surpasses the symbol. They are both so closely connected with this image that they dwell in it, not only as regards our way of conceiving the matter, because of the relation of similarity, but really, with their substance and personality. This is so far the general reason that as God they are everywhere present, and also because, even if they were not already present everywhere in substance for that general reason, they have to be present in so perfect an impress and effluence of their most intrinsic, personal perfections and origins, just as the seal must be present in its counterpart. Indeed, unlike the material seal after an impression has once been made, they cannot even be thought of as removed from immediate contact with the impression, for the latter, which has existence only from them, also has existence only in them.”
-Matthias J. Scheeben in The Mysteries of Christianity.