In communion with the holy Mother of God
Mary is the perfect Orans (prayer), a figure of the Church. When we pray to her, we are adhering with her to the plan of the Father, who sends his Son to save all men. Like the beloved disciple we welcome Jesus' mother into our homes, for she has become the mother of all the living. We can pray with and to her. The prayer of the Church is sustained by the prayer of Mary and united with it in hope.
Source: Catechism of the Catholic Church (Vatican.va)