The solution came by distinguishing who Jesus is and what he is. The who refers to his person. Who is Jesus? He is the eternal son of the Father, existing for all ages, the Second Person of the Blessed Trinity. Then what is Jesus? Is he by nature God, man or both? The Council of Chalcedon clarified that once he became man, the second Person of the Trinity was both human and divine. Totally both. Jesus is one person, divine, with two natures, human and divine. Mary is the mother of the human nature, she did not create the divine nature. However, in reality, the total person of who Jesus is can not be separated from what he is. Therefore Mary is Mother of God. That is our feast for today.
Now all this is the theological view of today's feast. It is important for us to be aware of the dogma of our faith. We have been entrusted with a rich tradition. We should understand the basic elements of that tradition. However, what does this feast say to us, right here and now, as individuals struggling to serve God throughout our lives, not as theologians speculating on ways to formulate dogma. To answer this we should look at today's second reading from Paul's letter to the Galatians. God's plan was that his Son should be born of a woman so that we might become his adopted sons and daughters. The Eternal Word became man so he could become our brother. Jesus instilled his Holy Spirit in us so we could have the status, the ability to address God as Abba, Father.
Jesus came as one of us. We are now sons and daughters of God. Our prayers have weight. When we are troubled with the struggles of life, when our faith feels weak, when we wonder if God really hears our prayers, we have to remember the status we have received through Mary's participation in God's plan. She is the Mother of God. He has made us his adopted children. At Christmastime we celebrate God's presence among his people. He is Emmanuel, God With Us, not as an unapproachable ruler, but as our Father who cares about us. Today we pray for the faith to call upon him.
 The Council of Chalcedon was an ecumenical council that took place from October 8 to November 1, 451, at Chalcedon (a city of Bithynia in Asia Minor), today part of the city of Istanbul on the Asian side of the Bosphorus and known as the district of Kadıköy. It is the fourth of the first seven Ecumenical Councils in Christianity, and is therefore recognized as infallible in its dogmatic definitions by the Roman Catholic and Eastern Orthodox churches. It repudiated the Eutychian doctrine of monophysitism, and set forth the Chalcedonian Creed, which describes the "full humanity and full divinity" of Jesus, the second person of the Holy Trinity. This action thus set aside the findings of the Second Council of Ephesus in 449.