One of the ancient staples of Christian prayer is the Song of Mary, the Magnificat, found in Luke 1, after Mary and Elizabeth have their encounter with their respective unborn sons recognizing one another in utero. It has been associated with Vespers, or Evening Prayer, for many centuries, and the Anglican Prayer Book tradition is no exception. The 1662 Prayer Book appoints it for Evening Prayer every day, all year, only replacing it with a Psalm when its text will appear in a lesson that day. Subsequent Prayer Books, including ours, do not make that rule explicit, and so we technically do have more leeway with replacing the Magnificat with another Canticle, but in the spirit of the prayer book tradition, we should not.
And with good reason – the Magnificat is a fantastic song-prayer. And its words are… startling. The first half of it celebrates what God has done with, in, and through Mary herself, and the second half of it celebrates what God has done for the whole world. “He has brought down the mighty from their thrones, and has exalted the humble and meek. He has filled the hungry with good things, and the rich he sent empty away.” Taken in a (very) anachronistic context, this could be an anthem for class warfare! But this is prophetic language – a survey of the Old Testament prophets will yield multiple hits of phrases like these. The work of God, however spiritualized and gospel-centric you describe it, still yields real-work effects. Sometimes such in-breaking of the Kingdom of God can resemble all sorts of political and economic and social theories without actually confining itself to any one of them. So while one can not read the Magnificat as a socialist manifesto, one can see elements of a socialist ideal drawn from the Magnificat. Sure, Marx was an anti-religious nut who didn’t always know what he was criticizing, but that didn’t stop him from absorbing select elements of the Gospel.
The Kingdom of God is like that… it gets everywhere and changes the world in all sorts of ways, whether every individual accepts it wholesale or not.
Meanwhile, regarding the first half of the Magnificat, we can learn a startling amount about the Blessed Virgin Mary herself. Since we’re in the the midst of Advent now, and that’s basically the only time of year most Protestants dare breathe the name of Mary out loud, let’s talk about her. What do Anglicans believe about the Virgin Mary?