Mary chooses a striking word for herself: 48"he has looked on the humble estate of his servant." The word means low standing, a life with no leverage in it. A young unmarried woman from an unremarkable village had nothing to bring to God but her consent. Four verses later she uses the same root for the pattern of God's work everywhere: 52"he has brought down the mighty from their thrones and exalted those of humble estate." What happened to Mary is Exhibit A for the whole song.
The song moves outward as it goes. It begins in the first person: 49"he who is mighty has done great things for me." Then it widens to whole categories of people, the proud, the mighty, the hungry, the rich. One private miracle in one obscure life becomes, in Mary's mind, proof of God's character toward everyone. She has understood something about how God runs the world, and she has understood it in the space of a single pregnancy.
That understanding arrives as matched reversals. 51"He has scattered the proud in the thoughts of their hearts." 53"He has filled the hungry with good things, and the rich he has sent away empty." Pride is scattered, thrones change hands, hunger is filled while wealth leaves with nothing. Mary sings all of it in the past tense, as settled fact, though from where she stands nothing has yet happened. In the child she is carrying, it already has.
It is an old song. Centuries earlier a woman with an impossible pregnancy stood at Shiloh and prayed that God "raises up the poor from the dust" (1 Samuel 2:8), and Mary sings the same convictions from a place where the answer is arriving inside her. Two women, separated by a thousand years, come to the same conclusion about how God builds his kingdom. He builds it out of the low being noticed and lifted, generation after generation, until the pattern is unmistakable.
The song ends where every act of Israel's God ends, in covenant faithfulness. 54"He has helped his servant Israel, in remembrance of his mercy, as he spoke to our fathers, to Abraham and to his offspring forever." This is the oldest promise in the Bible, now coming due. Everything Mary sings, her own lowliness noticed, the proud scattered, the hungry fed, is what it looks like when God keeps a promise he made long ago and never forgot.
Mary hears an angel's announcement and answers with a whole theology, sung aloud, of what kind of king is coming and what kind of kingdom he is bringing, one built for people of humble estate. Whenever you are tempted to measure your usefulness to God by leverage, platform, or standing, Mary's song answers back. He looks where the world stops looking. That was true of a girl in Nazareth with nothing to offer but her consent, and it is true of you.
Prayer
Father, thank you for a Savior who looks on lowliness. Forgive us for measuring our worth the way the world measures it. Teach us to sing Mary's song as our own, that you have done great things for us because you are merciful and never because we were mighty. Keep the promise you made to Abraham alive in us, generation after generation, until every proud thought is scattered and every hungry soul is filled. In Jesus' name, amen.