The Lutheran Symbols for Christmas

And in Jesus Christ, His only Son, our Lord, who was conceived by the Holy Spirit, born of the Virgin Mary - Apostles' Creed

And in one Lord Jesus Christ, the only-begotten Son of God, begotten of His Father before all worlds, God of God, Light of Light, very God of very God, begotten, not made, being of one substance with the Father, by whom all things were made; who for us men and for our salvation came down from heaven and was incarnate by the Holy Spirit of the Virgin Mary and was made man. -- Nicene Creed

But it is also necessary for everlasting salvation that one faithfully believe the incarnation of our Lord Jesus Christ. Therefore, it is the right faith that we believe and confess that our Lord Jesus Christ, the Son of God, is at the same time both God and man. He is God, begotten of the substance of His Father before all ages; and He is man, born of the substance of His mother in this age: perfect God and perfect man, composed of a rational soul and human flesh; equal to the Father with respect to His divinity, less than the Father with respect to His humanity. Although He is God and man, He is not two, but one Christ: one, however, not by the conversion of divinity into flesh but by the assumption of the humanity into God; one another, not by confusion of substance, but by unity of person. -- Athanasian Creed

Our Churches teach that the Word, that is the Son of God, assumed the human nature in the womb of the Blessed Virgin Mary. So there are two natures - the divine and the human - inseparably joined in one person. There is one Christ, true God and true man, who was born of the Virgin Mary... - Augsburg Confession

The human nature is assumed by the Word into the unity of His person. -- Apology to the Augsburg Confession

The Son became man in this manner: He was conceived, without the cooperation of man, by the Holy Spirit, and was born of the pure, holy, [and ever] Virgin Mary. -- Smalcald Articles

I believe that Jesus Christ, true God, begotten of the Father from eternity, and also true man, born of the Virgin Mary, is my Lord... - Small Catechism

We see how completely He has poured forth Himself and withheld nothing from us. -- Large Catechism

So we believe, teach, and confess that Mary conceived and bore not merely a man and no more, but God's true Son. Therefore she is rightly called and truly is "the mother of God." -- Formula of Concord

On account of the personal union and communion of the natures, Mary, the most blessed Virgin, did not bear a mere man. But, as the angel Gabriel testifies, she bore a man who is truly the Son of the most high God. He showed His divine majesty even in His mother's womb, because He was born of a virgin without violating her virginity. Therefore, she is truly the mother of God and yet has remained a virgin. -- Formula of Concord

Consider this majesty, to which Christ has been exalted according to His humanity. He did not first receive it when He rose from the dead and ascended into heaven. He received it when He was conceived in His mother's womb and became man, and the divine and human natures were personally united with each other. -- Formula of Concord

He employed this mode of presence when He left the closed grave and came through the closed doors, in the bread and wine in the Supper, and as people believe, when He was born in His mother. -- Formula of Concord