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https://joelssermons.files.wordpress.com/2019/12/20191201sermon.mp3
Texts: Isaiah 2:2-4; Luke 1:26-38
Note: Please see the postscript after the sermon from CMC member and OSU Department of Physics Lecturer Rick Leonard. He goes into more depth about the workings of sailing, corrects some poor physics in the sermon, and suggests another possible route for semonizing.
Back in August we had a family vacation by Lake Michigan. One of those days we took a ride on the Friends Good Will – a replica 1810 top sail sloop. Or, in words that I understand, a really cool, pretty old, good sized, sailboat. The original boat played an important role in the War of 1812 on the Great Lakes. The Michigan Maritime Museum in South Haven offers this ride as a way of experiencing what it’s like to be on such a boat, complete with an experienced crew running the ship and giving full commentary along the way. The out and back trip on the lake took about 90 minutes.
On the way out, the wind was mostly at our backs and we were mostly occupied with looking around the boat and watching the crew work the ropes on the sails. As we made the turn and started heading back the crew seemed unfazed by the fact that we were now sailing into the wind, the very force that had just been pushing us in the opposite direction. I knew that sailing upwind was a thing, and had likely had it explained to me multiple times before, but I forgot how it worked. When it was our turn to hang out on the captain’s deck, I asked him to help me understand what was going on.
I remember two things from this explanation. The first is that the curve of the sail acts much like the curve of an airplane wing, creating differing wind speeds and air pressures around the boat. The second – the one that still seems hard to believe except that it’s true – is that when you’re doing it right, when you’re sailing into the wind at the correct angle and those different wind speeds and air pressures are being created by the sails, the boat is actually being pulled forward by those forces rather than pushed.
Having graduated with a seminary degree and not a physics degree, my mind went instantly to sifting through the theological implications of this. But then I remembered that’s what I do for work, and I’m on vacation, so I should just enjoy the scenery.
And so there we were, enjoying the sights and sounds and smells, cruising along the shoreline of Lake Michigan, angling into the wind, our pretty good sized old top sail sloop, with us in it, whether or not we could understand how, being pulled toward our destination.
Today is the first Sunday of Advent, the beginning of the liturgical year. The final month of a calendar year that has been anything but smooth sailing.
Our Advent destination is a familiar one. We are headed through fear and pregnant expectation toward birth and incarnation.
Once again we must contend with the startling and tender scenes of this season, on display in lovely pastel, or whatever color you choose for your own copies: A young peasant girl who says Yes to a messenger claiming to represent God. A man pledged in marriage to this girl who chooses to be her advocate and partner rather than abandon her in shame. Unclean shepherds on the outskirt of town and society, the first to receive the good news of great joy that a child of peace has been born. The mother, step father, and child cradled by animals and angels. We arrive in Bethlehem with the sense that, after all these years, all this still has something to do with us.
Ever mindful of all the forces around us pushing us here and there, it is within this season especially when we might feel a different force at work. Something pulling us toward itself.
I wonder if this sense of being pulled into the headwinds is what the prophets had in mind when they spoke and wrote their words to the people of Israel.
In the form we have it on our Bibles, Isaiah begins with words of judgment. More specifically, a lawsuit. Isaiah declares that Yahweh is taking the people of Israel to court for violating the covenant of Moses. And the Lord seems to have a pretty good case. The people are keeping all the festivals and assemblies, but ignoring justice. The leaders take bribes, their own courts side with the strong over the vulnerable.
Facts on the ground seem to indicate that the judgment has already been made. The Northern Kingdom of Israel had recently been overrun by the Assyrians with the city of Jerusalem barely holding off the attack, now an island of resistance. Isaiah says to his people, “Your country lies desolate, your cities are burned with fire; in your very presence foreigners devour your land; it is desolate, as overthrown by foreigner. And (Jerusalem) is left like a booth in a vineyard, like a shelter in a cucumber field, like a besieged city.”
But then, this: “In days to come, the mountain of the Lord’s house shall be established as the highest of the mountains and shall be raised above the hills; all nations shall stream to it. Many peoples shall come and say, ‘Come, let us go up to the mountain of the Lord.’ …They shall beat their swords into plowshares, and their spears into pruning hooks.; nation shall not lift up sword against nation, neither shall they learn war any more” (Isa. 2:2-3a,4b).
Rather than more desolation, that shelter in the cucumber field finally collapsing, Isaiah offers this peaceful vision for, as he says it, “days to come.” A common point where all the nations gather. Where everyone gets the education and instruction they need to live well. Where technologies formerly used for war are adapted for agriculture – “swords into ploughshares.” “They shall learn war no more.” The military schools get shut down and repurposed as schools for the arts and sciences. The national defense budget sinks to zero, all its resources diverted to the newly prominent department of gardening.
Isaiah gives no indication of how or when we might arrive at such an arrangement. He simply describes the destination and notes that all journeys converge at this site. As if pulled by the very vision itself laid out by the prophet.
This public declaration for all to hear, even all the nations, stands in contrast to the private exchange between the angel Gabriel and the young Mary. This takes place many centuries after Isaiah, in the rural hinterlands north of Jerusalem – Nazareth in Galilee.
This is the scene of our first poster. The word angel means messenger, and messages come in a thousand forms, so it’s always an act of imagination to draw what that messenger/angel might have looked like. Just for the record, I think they got it right to have the angel barefoot and slanted, between heaven and earth.
Mary, for her part, looks to be entirely earth bound. Subject to the same forces for gravity and mortality as the rest of us. It is her humanity that sets her apart from the angel. She is a creature of flesh and muscle, bone and brain. Whole and individual in her self. And, miracle of miracles, one with the capacity to hold within her own body the formation of another such being. Mary, with the fortitude and willingness to say Yes to this surprising and terrifying task. “The Holy Spirit will come upon you,” the messenger says. “And the power of the Most High will overshadow you; therefore the child to be born will be holy.” Mary looks over the slanted barefoot messenger up and down a long time, pondering, as she was wont to do.
This was not a command from the angel. Not a command. It was an invitation. There was no coercion. It was up to Mary to accept or decline. Who’s to say Gabriel hadn’t visited thousands of others for hundreds of years before appearing to Mary? The words above Mary’s head in the image, halo-like, are a loose paraphrase of her response as noted in Luke’s gospel: “I will carry God in my body. Yes.”
It’s Mary whose journey mirrors our own through Advent. We move from uncertainty to assent, and, long after the messenger has moved on, we live with the message as it grows inside us, rearranging our priorities, asking more of us than we could first imagine.
And it’s Mary who provides a picture of what it might mean to move toward a destination into the prevailing winds.
We are a congregation that cares deeply about the well-being of our world – our neighbors near and far. Many of us spend most of our best energy throughout the week trying to make the world look a little bit more like the peaceful vision of Isaiah and a little less like the desolation of the Assyrians. We fail regularly, and sometimes our own lives look like the Assyrians busted in and had a heyday.
Who’s to say how many Yes’ large and small are said each week by all of us? Each Yes an act of assent to the invitation of God.
The downside of loving this world of flesh and bone and persons and politics, is that the wind is so frequently blowing in our face.
And Just in case you’re wondering, we are indeed going to ride this sailing metaphor all the way through to the end, so please stay on board.
What’s striking about Isaiah and Gabriel is that neither of them counsel their listeners to simply row harder. Wind creates resistance, so the solution could be to row harder. The harder we row the faster we go, and the sooner we reach the mountain of the Lord, the savior of the world.
Instead, Mary is asked to become a sail for God.
The science of sailing teaches that when angling into the wind, the sail creates its own micro climate. The rushing air forms a high pressure system behind the sail and a low pressure system in front of it. It is that low pressure out in front that pulls the sail, and the boat, and everyone in the boat, into itself. As soon as the boat moves forward with the sail, so too does that low pressure area, which continues to pull the boat toward its destination. The sail need only be itself, oriented in the right direction.
I’ve seen plenty of sailing illustrations for how we are to catch the wind of God’s Spirit to propel us through the waters of life. This one’s a little different. Because what feels truer to life is that the wind is actually trying to blow us in the wrong direction. A life of love and generosity and kindness and forgiveness and peace, a life of hope in the word for the day also on the poster, is much more like sailing into the wind.
God is a destination, the universal peace toward which we orient our lives. The meeting place of all nations and peoples.
God is that small gap between us and the winds coming at us. That low pressure presence which draws us toward itself and, as soon we are propelled in its direction, moves just that far in front of us to keep drawing us toward itself.
And God is the one who comes to us in need of a boat. Like Gabriel’s invitation to Mary. God too needs a way to move into the wind, and needs someone to catch the wind in a certain way to carry God forward through troubled waters.
Destination, low pressure pull, sailor in the storm. Three in one, blessed Trinity.
Our Yes is God’s permission to board the ship. It is our willingness to be nothing more and nothing less than ourselves, whole and individual.
As God is born into this world through us.
As God transforms swords into plowshares.
As God harnesses headwinds to sail toward peace.
I certainty applaud usage of your observations of the physical world, and corresponding attempts to understand its workings, to provide a counter context for sermon messages. You don’t even have to “get it right”, so to speak. It’s entertaining and stimulating if not necessarily insightful. In this case, though, I must inform you that your basic premise in “Pulled Toward” is simply wrong.
When that sailboat is out there on the water it is being ‘pushed’. In no sense is it being ‘pullled’. In fact, this is what is so interesting about sailing upwind, which is the fascinating capability in sailing that is your focus. Yes, it is tempting to seek some kind of ‘attractive’ force as an explanation, but the forces involved are really quite mundane. It’s just bodies pushing against each other, for which the ultimate explanation is the purely repulsive force between the atoms of the materials.
There are two misconceptions to deal with. First, forget, for a moment the idea of the “Bernoulli” effect on an airfoil or, in this case, a curved sail. This is interesting but not at all essential. (I don’t know exactly what your captain told you, but I’ll give him or her the benefit of the doubt, that you merely failed to completely understand what you were told.)
So, let the sail be perfectly flat and rigid. When oriented at any angle to the wind, the sail will deflect the wind and thereby change the wind’s momentum backward and perpendicular to the sail. Correspondingly, the wind gives an equal and opposite momentum to the sail. (This is Newton’s 3rd Law, or, equivalently, conservation of momentum.) So, the wind pushes the sail in a direction generally in the direction of the wind but only perpendicular to the sail.
The other misconception, which is really crucial, is what is left out of the explanation. There is another body: the water. The water also pushes on the boat but ‘under’ the surface on the ‘keel’. The keel prevents the boat from going any direction but along the boat. That is, the boat is prevented from going ‘sideways’. We, of course, normally want the boat to go ‘forward’ along the keel, but it could be forced to go ‘backward’ along the keel, as well.
So, the wind interacts, repulsively, with the sail, and the water interacts, repulsively, with the keel. In most ordinary configurations of sail relative to wind and keel relative to wind, the boat is forced forward along the keel in a generally downwind direction. However, if we angle severely enough somewhat upwind, then the resulting combination of the wind and water forces can actually be at this generally upwind direction.
It is not possible to go directly against the wind, but one can go at this rather large angle to the wind. To go directly against the wind, one must zigzag or ‘tack’ back and forth. You may have observed that in your voyage.
The orientation of the sail must be at a small angle with the keel for this to work. Then, the sail will then be nearly lined up with the wind. So, it’s actually not ‘catching’ much of that wind.
Here’s where the Bernoulli effect on a curved sail becomes part of the explanation. The wind is curling around the sail very much like the air around an airplane wing. The wind is being deflected in this curved path, which, by the same action-reaction Newton’s Third Law, causes the sail to be pushed the other direction.
Yes, that Bernoulli effect also involves those pressure differences that your captain described. This is an interesting aspect of the effect, but it’s actually somewhat distracting for our explanation. On the ‘long and fast’ path the pressure is lessened, and on the ‘short and slow’ path the pressure is increased. So, you also get a pressure difference from greater to lesser that pushes the sail. Note, though, the air is ‘pushing’ on both sides. It just pushes harder on the upwind side. Overall, the wind, by whatever mechanism, is pushing downwind.
So, when you use this analogy again (as you certainly must), it will be very important to involve the obvious ‘push’ of the ‘wind’ above the surface along with the less obvious ‘push’ of the ‘water’ below the surface. The two, wind and water in concert, can enable us to go against the force of nature, so to speak. Perhaps, you see the germ of a sermon, but that, of course, is your job.
With love and respect,
Rick