He does point out that it is a "secret".
He also says:
7. The saints have said wonderful things of Mary, the holy City of God, and, as they themselves admit, they were never more eloquent and more pleased than when they spoke of her. And yet they maintain that the height of her merits rising up to the throne of the Godhead cannot be perceived; the breadth of her love which is wider than the earth cannot be measured; the greatness of the power which she wields over one who is God cannot be conceived; and the depths of her profound humility and all her virtues and graces cannot be sounded. What incomprehensible height! What indescribable breadth! What immeasurable greatness! What an impenetrable abyss!
What breathtaking blasphemy
This kinda got lost among all them thar other words...