The Magnificat is the centrepiece of Mary as the parable of the Church, and  Luther reads it in exactly that way.

-- Mark E. Chapman, Lutheran pastor  and theologian

Extract from Jesus, Mary and Martin by Darel E. Paul

The Magnificat is the name of the Blessed Virgin Mary's hymn of praise to  God, found in Luke's gospel. It is named thus for the first words of the  canticle in Latin, "magnificat anima mea Dominum, et exultavit spiritus meus  in Deo salutari meo". In this hymn, Mary shows us the nature of God, and instructs us upon a right response to His goodness. Luther takes up the  Magnificat precisely to demonstrate how "the tender Mother of Christ . . .  teaches us, with her words and by the example of her experience, how to know,  love, and praise God." (Works, vol. 21, p. 301) Furthermore, Luther addresses his commentary to his patron, John Frederick of Saxony, stating that "in all of Scripture I do not know anything that serves such a purpose so well as this  sacred hymn of the most blessed Mother of God, which ought indeed to be learned and kept in mind by all who would rule well and be helpful lords." (p. 298) Clearly, Luther considered the Magnificat a most significant passage of  Scripture, and by extention the Virgin Mary, Mother of God, as a most high  instructor in the faith.

As a point of departure, we should first be  acquainted with the hymn itself.

 

My soul magnifies the Lord,
and my spirit rejoices in God my Savior
for he has regarded the low estate of his handmaiden.
For  behold, henceforth all generations will call me blessed;
for he who is mighty has done great things for me,
and holy is his name.
And his mercy is on  those who fear him
from generation to generation.
He has shown strength  with his arm,
he has scattered the proud in the imagination of their hearts,
he has put down the mighty from their thrones,
and exalted those  of low degree;
he has filled the hungry with good things,
and the rich he  has sent empty away.
He has helped his servant Israel,
in remembrance of  his mercy,
as he spoke to our fathers,
to Abraham and to his posterity for  ever.
(Luke 1: 46b-55, RSV)

The central element of the Magnificat in Luther's eyes is Mary's response to the angel of the Lord, who in  the Annunciation reveals God's plan of salvation to this lowly woman, little  more than a girl.

Mary trusts and believes

"My soul magnifies the Lord." These are the first words of praise. For Luther, they signal the Blessed Virgin's total dedication to the work of God.

But Mary says, ‘My soul magnifies Him' -- that is, my  whole life and being, mind and strength, esteem Him highly. She is caught up, as it were, into Him and feels herself lifted up into His good and gracious will. (p. 307)

Recall Mary's response to the angel Gabriel -- "Behold, I am the handmaid of the Lord; let it be to me according to your word." Mary responds to the Annunciation with trust in the plan of God and belief in the promise that she, though a virgin, will bear a son. And even more, that this  son

will be great, and will be called the Son of the Most  High;
and the Lord God will give to him the throne of his father David,
and he will reign over the house of Jacob for ever;
and of his kingdom there will be no end. (Luke 1: 32-33)

Mary

lets God have His will with her and draws from it only a good comfort, joy, and trust in God. Thus we too should do. (p.  309)

Mary rejoices and praises God

"My spirit rejoices in God my Savior, for he has regarded the low estate of his  handmaiden." So says the Mother of God. Mary not only instructs us to rejoice in the gifts that God has given, but by her example shows us how to do so. Mary  does not boast in that which God has done for her. In Luther's words,

Mary confesses that the foremost work God did for her  was that He regarded her, which is indeed the greatest of His works, on which  all the rest depend and from which they all derive. For where it comes to pass  that God turns His face toward one to regard him, there is nothing but grace and  salvation, and all gifts and works must follow. (p. 321)

Mary goes on to say,

For behold, henceforth all generations will call me  blessed;
for he who is mighty has done great things for me,
and holy is  his name.

Indeed, "all generations will call me blessed". But  why? For what Mary has done, bearing the Son of God? For who Mary is, the holy  Virgin, chosen Mother of God? No. "For he who is mighty has done great things  for me". Mary is to be called ‘blessed' for the works of God, not the works of Mary. The Blessed Virgin recognizes her lowliness, and directs us to praise God for His great deeds done through the willingness of this woman.

Mary humbles herself before God

Mary deserves the highest praise that  human beings can give. Luther tells us
men have crowded all her glory into a single word, calling her theotokos. No one can say anything greater of her or to her,  though he had as many tongues as there are leaves on the trees, or grass in the  fields, or stars in the sky, or sand by the sea. It needs to be pondered in the heart what it means to be the Mother of God. (p. 326)

Yet  what is the nature of this most lofty station? Has Mary earned it by her merits?  Luther repeats the teachings of the Church catholic that Mary lived without sin (p. 327). Yet this did not entitle her to become the Mother of God. She did not look for this blessing, but it came upon her suddenly and unexpectedly. If Mary has deserved such status, she would have expected the angel to come to her and deliver his message. Instead, Luther tells us,

The tidings took her all unaware, as Luke reports [Luke  1: 29]. Merit, however, is not unprepared for its reward, but deliberately seeks and awaits it. (p. 327)

Luther also teaches that Mary is rightly called Regina coeli, 'Queen of Heaven'. To most Lutherans, this is a most surprising discovery! Has Mary earned this title by her merits?  Certainly not, says Luther, for she is Queen by grace, not reward.

We are thus left in a difficult position. Mary is not to be praised for her merits or  accomplishments, yet is, as Luther states elsewhere, the "noblest gem in  Christianity after Christ". How then are we to approach the Mother of God? Are  we to approach her at all?

Many if not most Lutherans consider an address to the Blessed Virgin pointless at best, idolatry at worst. Yet Luther himself felt quite differently. He invoked the Blessed Virgin in the introduction to the  Magnificat itself, saying

May the tender Mother of God herself procure for me the  spirit of wisdom profitably and thoroughly to expound this song of hers (p. 298)

He concludes the commentary with the words:

We pray God to give us a right understanding of this Magnificat, an understanding that consists not merely in brilliant words but in glowing life in body and soul. May Christ grant us this through the intercession  and for the sake of His dear Mother Mary! Amen. (p. 355)

This is certainly not a case of Luther's idiosyncracies, either, for the Apology of the Augsburg Confession itself acknowledges that Mary lives in heaven and prays to her Son for the Church militant.

Luther,  however, was keen to place Mary in a right relation to God the Father and to God  the Son. He condemed the practices of his day which elevated Mary to a high  station when she herself admits only her "low estate" (Luke 1: 48). Those who praise the merits of the Virgin in fact

spoil the Magnificat, make the Mother of God a liar, and diminish the grace of God. (p. 322)

He especially  condemned those who looked to Mary for aid and comfort when they should instead look for it in God Himself. Luther was guilty of this practise as a young man, and thus was particularly critical of it in later life. Before and after the  Reformation, Roman Catholics have justified giving prayers to Mary rather than to Christ on the basis of a belief that Jesus is a severe lawgiver to be feared, while Mary instead is a tender mother who only offers comfort. Witness the words  of the Curé d'Ars, a 19th century French priest: "The holy Virgin is so kind that she always treats us affectionately and never punishes us. The Son wields His justice, while the Mother wields nothing but love."

Nonsense! says Luther. First, such talk diminishes the grace of God, who bestowed blessings upon Mary out of His own goodness, not out of Mary's goodness. Second, it  violates the Mother of God's own wishes.

all those who heap such great praise and honor upon her  head are not far from making an idol of her, as though she were concerned that  men should honor her and look to her for good things, when in truth she thrusts  this from her and would have us honor God in her and come through her to a good  confidance in his grace. (p. 322)

Mary does nothing herself. There is no reason to believe prayers offered through Mary are heard more or better than those offered without her intercession. The only reason we might care to call upon the Blessed Virgin is to invoke her example and pray to God  that he may do unto us as He did unto Mary, that is, show his unlimited grace in our lives which we in no way can deserve or merit.

Luther notes throughout the Magnificat that we do not owe praise to the Blessed Virgin Mary. This would call attention to her merits, her greatness, her powers, when, being a creature of God, she has none. What we do owe her instead is honor and  devotion (p. 322). Why honor? For being the Mother of God, the greatest honor that God has bestowed on any of his creatures of any site or century. Why devotion? For she is the tender Mother who served Christ when he was but a baby,  and whose willingness to act as God's servant made the salvation of the world possible. Why her example, apart from the examples of saints throughout the  ages?

She should be, and herself gladly would be, the  foremost example of the grace of God, to incite all the world to trust in this  grace and to love and praise it, so that through her the hearts of all men  should be filled with such knowledge of God that they might confidently say: 'O  Blessed Virgin, Mother of God, what great comfort God has shown us in you, by so graciously regarding your unworthiness and low estate. This encourages us to believe that henceforth He will not despise us poor and lowly ones, but  graciously regard us also, according to your example.' (p. 323)

In the Magnificat, Mary continues to show us the great works of God: mercy, breaking of spiritual pride, putting down the mighty, exalting the lowly, feeding the hungry, and sending the rich away empty. She  reminds us that our God is a God of the lowly, the humble, the weak, the poor,  the anonymous. In many ways the Blessed Virgin herself was all of these things, making her even more the model of our faith. By her experience, shown in the Magnificat, the Blessed Virgin shows us "how to know, love and praise God." (p.  301) We should ask no more and no less of this Saint Mary, Mother of Our Lord.