Mary's prophecy in Luke 1:46-55 is justifiably famous. One of the few formally-structured speeches in scripture by a woman, and in the form of a psalm (see for instance, Psalm 8), this is praise to God in thanks for his work ("he who is mighty has done great things for me", v 49) and in recognition of God's goodness "to those who fear him", v. 50.
True to Luke's emphasis in his two books, the Holy Spirit is shown leading Elizabeth to bless Mary (v. 42-45). It seems in context to give credit to the Holy Spirit for Mary's song of praise also. We could imagine that Mary had been thinking of some of these words during her trip to see her cousin, and holding on to these words (see 2:51b), giving them to Luke years later, perhaps for more literary stylizing as well.
The first portion, 46-49, is a joyful song of praise to the Lord. “My soul magnifies the Lord, and my spirit rejoices in God my Savior, for he has looked on the humble estate of his servant. For behold, from now on all generations will call me blessed; for he who is mighty has done great things for me,
and holy is his name." It seems a little forward to imagine "all generations" referring to her in the future, but again, this is formal speech, and as it turns out, she was right.
What can we learn from this? Several different lessons, I believe. First, the responsibility, or perhaps better, the opportunity or privilege, of thanking God for what he does for us; recognizing his generosity, as a child would thank a parent for an ice-cream cone. Second, that we can gain a humble perspective by reflecting on his power and authority, ("he who is mighty") which is so far above ours, yet he takes notice of us and wishes to bless us ("has done great things for me").
The second half of this song has a more difficult tone, and we'll look at that tomorrow.