Recall how the heretic Nestorius wrongly believed that in Christ there was a divine eternal person and a human created person united in common cause. Nestorius incorrectly set forth "two persons" or "two Christs."
The Catholic Church condemned Nestorius' doctrine, since Christ is one Person with two natures. He is fully divine and fully man without confusion or mingling.
Now Saint Maximilian shows us that what Nestorius got wrong about Christ, may in fact be close to correct when we consider the Blessed Virgin Mary and the Holy Spirit. They are two persons (one created, one uncreated), united in purpose.
Kolbe cites the usage of St Francis: Mary is "Spouse of the Holy Spirit" in order to describe their intimate union. Moreover, the Holy Spirit is "uncreated Advocate" and Mary is "created Advocate." Advocacy for the Church is their common cause. Since Mary is full of grace and full of the Holy Spirit, her will, prayers, and advocacy mirror that of the Holy Spirit. E.g. "the Spirit and the Bride say..."
Kolbe uses the phrase "quasi-incarnation of the Holy Spirit" for Mary. I feel just a little uncomfortable with that description, but I see what he is saying.
If we see Mary as a created manifestation of the Holy Spirit, then the link between Pentecost and the Assumption (as in the Rosary) becomes even stronger. This description of Mary as Spouse of the Holy Spirit may be helpful in how present Mary to Protestants who do not understand our devotion to her. It's not that Mary is a divine person of the Holy Trinity. Rather, Mary is created manifestation of the Third Person of the Holy Trinity.
ad Jesum per Mariam,
PS: I seek to follow Saint Maximilian Kolbe with regard to Blessed Mary and the Holy Spirit. If I have overstated anything or not followed the mind of the Church, I humbly repent and ask that it be disregarded. Filius Ecclesiae et Mariae sum.