Today, some people are saying it is "plain water." The devil take them! My dog Toelpel, a wild boar and a cow know that. But what else is there? Without doubt, in baptism we get God -- Father, Son and Holy Spirit -- and all the angels! So, it is no longer "plain water," but water in which the Son of God bathes, over which the Holy Spirit hovers, over which God the Father preaches.
... It is not I that baptize, but God and all the angels -- they show up on their own.
--Luther, in a sermon preached 6 January 1534
There's a lot more there, for those who are interested and have access to the ATLA database. The sermon is translated by Frederick Gaiser, and appeared in Word & World, Winter 1996.
Briefly, Luther's sermon is highly, even archly Trinitarian; it makes good use of the Small Catechism's Augustinian distinction between plain water and water to which the Triune Name has come; and it goes out of its way to argue that baptism is not a human work but a divine one.
Spiritually, we are touched by the way Luther works the angels into his vision of baptism; we aren't sure they belong there, except of course that they are God's entourage. Liturgically, it is worth noting that 6 January was in those days a celebration both of the appearance of and to the Magi, and of Jesus' own baptism. Luther makes quite a point of saying that the baptismal story is the more important, and deserves to be celebrated independently.
There's a at least one typical "Oh, Uncle Marty" moment, which is a little hard to capture. Distilled spirits were often called aqua vitae, the water of life -- in other words, akvavit. So, in Gaiser's rendering, Luther says:
[Baptismal water] becomes a precious ointment and medication because God has stirred himself into it. That's why it is the genuine Aquavit.By which he means:
... Whoever is in sin, stick them in the baptism[al water], and their sin will be extinguished. Whoever is in death, stick them in the baptism[al water], and death will be swallowed up. For baptism has divine power, the power to break sin and death.Good stuff for Sunday, if you need a little inspiration.