Today the Church celebrates the Solemnity of Mary, the Holy Mother of God. It is our Lady's greatest title.
This feast is the Octave of Christmas.
The Catechism of the Catholic Church (#271) states: "Mary, the all-holy ever-virgin Mother of God, is the masterwork of the mission of the Son and the Spirit in the fullness of time. For the first time in the plan of salvation and because his Spirit had prepared her, the Father found the dwelling place where his Son and his Spirit could dwell among men. In this sense, the Church's Tradition has often read the most beautiful texts on wisdom in relation to Mary. Mary is acclaimed and represented in the liturgy as the "Seat of Wisdom."
The English title "Mother of God" is a literal translation of the Latin title Mater Dei, which in turn is a rendering of the Greek title Θεοτόκος (Theotokos), meaning "Bearer of God" dogmatically adopted by the First Council of Ephesus (431) as an assertion of the divinity of Christ.
O God, who through the fruitful virginity of Blessed Mary bestowed on the human race the grace of eternal salvation, grant, we pray, that we may experience the intercession of her, through whom we were found worthy to receive the author of life, our Lord Jesus Christ, your Son.