In his wonderful book on the Holy Spirit, The Sanctifier, Archbishop Luis Martinez notes that there are two sanctifiers of souls. 1) the Holy Spirit, Who is the essence of Holiness and 2) Mary, His spouse, who is the Mediatrix of all the graces He wishes to bestow upon us. The purpose of sanctification is ultimately to transformed into Jesus Christ, in a particular way.
The Apostle's creed reads “I believe in God, the Father almighty, Creator of heaven and earth, and in Jesus Christ, his only Son, our Lord, who was conceived by the Holy Spirit, born of the Virgin Mary...” and so on and so forth. This section of the Creed is based on St. Luke's Gospel:
Behold thou shalt conceive in thy womb, and shalt bring forth a son; and thou shalt call his name Jesus. He shall be great, and shall be called the Son of the most High; and the Lord God shall give unto him the throne of David his father; and he shall reign in the house of Jacob for ever. And of his kingdom there shall be no end. And Mary said to the angel: How shall this be done, because I know not man? And the angel answering, said to her: The Holy Ghost shall come upon thee, and the power of the most High shall overshadow thee. And therefore also the Holy which shall be born of thee shall be called the Son of God. (Luke 1:31-35)
This doctrinal declaration has a spiritual dimension that is meant to take place in us. What literally happened with the Blessed Mother by the power of the Holy Spirit is meant to take place in us in a spiritual way. As Martinez says, “That is the way Jesus is conceived. That is the way He is reproduced in souls.”1 As we shall see, this is the goal of our lives: to become like Christ, to let the Divine Artist of Souls (the Holy Spirit) paint Christ in and on us. First, however, we must understand Mary's role in this since Scripture and Tradition intimately link Her and the Holy Spirit to the roles of sanctifying souls.
In his book, True Devotion to Mary, St. Louis de Montfort explains the idea of Mary as the Mediatrix of all graces from God: