From the writings of St. Maximilian Kolbe
God the Father loves from eternity. His Love can only find an eternal response appropriate to Him, i.e., the Son. From the Love of Father and Son for each other “proceeds” the Holy Spirit. God’s Love and His Being are one and the same.
So why is it that the Holy Spirit came upon Mary?
Because He is nothing less than the Love of God, proceeding from the Father and the Son. The Holy Spirit is the fruitfulness of God’s Love, of Father for Son and Son for Father. This is why we confess the Holy Spirit as “the Lord and Giver of Life.” It was the “Spirit of God” that breathed upon the waters (Genesis 1:2).
God’s Love, the Holy Spirit, gives life at the beginning of creation, and gives life at the beginning of the new creation in the womb of Mary. And just as the love of the Father and Son for each other leads to the Holy Spirit, who “proceeds” for them (words which begin to crack when we recognize we are applying them to categories of eternity), so the Holy Spirit begins the work that leads man back to the Father.
For it is the Spirit Love of God that conceives the Son, and the Son who, by His death and resurrection, reconciles man to the Father and sends the Holy Spirit upon humanity to continue that work of sanctification.
But He did it through Mary for—as St. Louis-Marie Grignion de Montfort notes—the Holy Spirit realizes His fertility not within the Trinity (since He neither begets any divine Person nor does one proceed from Him) but, with Mary, in fashioning the human nature of Jesus. It’s not that the Spirit needs Mary to express His life-giving lordship but, with her, He reveals God’s radical desire to make humanity in God’s own image in a supernatural way that man could never have conceived (see 1 Corinthians 2:9). He gives life to the Divine-human Person of Jesus Christ, who leads His brothers and sisters into a filial relationship to the Father that Adam could never have imagined (Romans 8:15). That’s what we mean by felix culpa!
The Spirit is the Love of the Father and the Son, the love with which God loves Himself, the love of the whole Most Holy Trinity, fruitful love, conception. If marital love leads to “two in one flesh,” then how much more intimate is that perfect love, perfectly accepted by the human being Mary, which makes her fruitful, and that from the first moment of her existence for her whole life, i.e., forever.
And since the Holy Spirit is the agent of human sanctification (remember, we are made into Temples of the Holy Spirit [1 Corinthians 6:19] who prays in us [Romans 8:26]), is it not fitting that His Spouse should be an intercessor for our salvation? Jesus gives us Mary as His Mother (John 19:27), but the Holy Spirit gives us Mary as she who, with Him, is concerned for our sanctification. “Mary, as the Bride of the Holy Spirit, and therefore high above every created perfection, thoroughly accomplishes the will of the Holy Spirit who dwells in her, and that from the first moment of her conception.
For if, through her, Mary’s Spouse launches the work of sanctification by the conception of Jesus, then Mary—free of the stain of sin—is no indifferent bystander to that work. Making her will His, she cannot not be joined to the battle against sin and death that her Son’s life, death and resurrection will win.
And so, in the return to God, the equal and opposite reaction proceeds in the opposite way to that of creation. In the case of creation, [all comes] from the Father through the Son and the Spirit, while here, through the Spirit, the Son becomes incarnate in the womb of her and, through Him, love returns to the Father. She then, woven into the love of the Most Blessed Trinity, becomes from the first moment of her existence, forever, eternally, the complement to the Most Holy Trinity.
Musical Selection (Archangel Voices)
The apostles, beholding the descent of the
Comforter, were amazed, how the Holy Spirit
appeared in the form of fiery tongues.
Rejoice, O Queen! Glory of mothers
and virgins! No mouth, however sweet or
fluent, is eloquent enough to praise you
worthily! Every mind is over-awed by your
childbearing! Therefore with one voice we
glorify You!