And you, child, will be called the prophet of the Most High;
for you will go before the Lord to prepare his ways.
—Luke 1:76


Before Luke tells us the story of the birth of our Lord, he tells us the story of the birth of John the Baptist, Jesus’ cousin and campaign manager. John was born three months before Jesus, to an old priest named Zechariah and his wife Elizabeth.

Luke tells us three important things about Zechariah and Elizabeth: Luke tells us first that they were devout Jews—‘blameless’ is how Luke describes them—and second that they were childless; and finally that they were old. Luke doesn’t tell us how old, but in my mind’s eye I picture a 60-something couple who’ve already explored retirement communities on the shore of the Dead Sea, the Florida of ancient Palestine. The salient point is that Elizabeth had her hot flashes long ago.

Zechariah works at the Temple in Jerusalem. One day when he’s in there minding his own priestly business, the angel Gabriel interrupts him and tells Zechariah that his 60-something wife Elizabeth is pregnant with their son. Zechariah, who knows how these things work, says to the angel, “No way!” And the angel says “Way!” or something like that.

And Zechariah says, “Prove it!” Zechariah’s insolent skepticism ticks Gabriel off, and he says to Zechariah, “All right, I will prove it. Those incredulous words you just spoke? Those are the last words you’ll speak till that baby is born and you see it with your own eyes.”

And so for nine months, Zechariah doesn’t say a word, tough ordeal for a clergyman. The baby is born, and it’s time to give the baby a name. Zechariah has a little pad and pencil hanging from a string around his neck, and he takes it and on the pad he writes, “His name will be John.”

And just as he writes these words, his tongue stops sticking to the roof of his mouth and he can talk, and after nine months of silence the words he speaks are replete with a pent-up eloquence.

Zechariah’s little speech is often called the Benedictus, after its first word in Latin: “Blessed be the Lord God of Israel, for God has looked favorably on God’s people and redeemed them. God has raised up a mighty Savior in the house of David, so that we will be saved from our enemies and from the hand of all who hate us… By the tender mercies of our God, the dawn from on high will break upon us, to give light to those who sit in darkness and in the shadow of death, to guide our feet into the way of peace.”

Once again, that melody, that leitmotif (pun intended) that keeps coming back whenever we hear about Jesus. He is the light of the world. He is the dawn from on high that breaks upon a lost people sitting around in a darkness so thick you can touch it. In the Gospels, ‘Light’ proves to be an irresistible and irrepressible metaphor to describe what Jesus means to so many people.

In the Gospel of Luke, after Zechariah’s beautiful Benedictus, the Evangelist will tell us that there were shepherds watching over their flocks by night and the glory of the Lord shone round about them.

In Matthew, a brilliant, lucent new star will guide Magi to the new King’s cradle.

John tells us that Jesus is the Light of the World. “The light shines in the darkness and the darkness cannot overcome it.”

It’s easy to see why ‘Light’ proves to be an irresistible metaphor for the meaning of the child born at Bethlehem. Among all the other staples of human existence the Evangelists liken Jesus to—the Bread of Life, the Living Water, the Vine—Light is the most fundamental and indispensable to human thriving.

Without light, we cannot see. Without light, we would be lost. We could never find our way through the night. Only in his brightness does the murky world make sense.

Without light, we would freeze; without the perfect amount of the sun’s heat and light, life would not be possible on this Goldilocks planet—not too warm, not too cold.

Without light, we would starve; the grain that sustains our metabolisms is nothing but synthesized starlight, and the soil it grows in is nothing but stardust from dead ancient suns.

Without light we would be lost. Without light we would be cold. Without light, we would be hungry.

And this fall, I was reminded of a fourth reason this metaphor of Jesus as the Light of the World is so apt. Matthew, Luke, and John didn’t know this, of course, but they still got it right 2,000 years before Albert Einstein: Light is the one fixed and unchanging constant in the universe. It’s all relative to the Light.

This fall, the media have been celebrating this revolutionary anniversary. Last month—November 25—was the 100th anniversary of Dr. Einstein’s Theory of General Relativity. Ten years before that, in 1905, he’d given us Special Relativity, and together, they are probably the most revolutionary discoveries in the history of science. It’s for that reason that the United Nations has named 2015 the International Year of Light.

So I’ve used this epochal anniversary as an excuse to revisit all the math and physics that are stumbled through during high school and aggressively avoided during college. I’m not very good at it, but I’m awed by it, and anyway who does understand it?

When General Relativity was still a pretty new concept, someone came up to the great Cambridge astronomer Arthur Eddington and said, “Dr. Eddington, I’ve been told that there are only three scientists in the world who understand General Relativity, and that you are one of them.” Dr. Eddington said nothing; Dr. Eddington was a Quaker; his shyness and humility were legendary. His interrogator said, “Dr. Eddington, don’t be so modest.” Dr. Eddington said, “On the contrary. I’m just trying to think of who the third one is.”[1]

All that is very true, but actually the Theory of Special Relativity is very simple. It simply says that the laws of physics are the same whether you are in motion or at rest. That’s all there is to it.

But of course the implications are staggering. What it means to say is that no matter how fast you are traveling relative to a beam of light, the light beam still travels at 186,000 miles a second. If you’re running alongside this beam of light at 90% of its speed, or away from it at the same speed, the light is still going at 186,000 miles a second.

But if this is true, of course, then space and time are not fixed and constant. Once we thought a mile was a mile was a mile and a minute was a minute was a minute, but now we know they’re not. The shortest distance between two points is not a straight line, because space is curved, and if you and I are moving at vastly different speeds, we each have our own clocks, and they’re not the same. The faster you go, the slower your clock moves.

There was a time when we thought that space and time were fixed and constant. A mile was a mile was a mile, and a minute was a minute was a minute, but now we know that space and time flex and bend, quite literally; they are not straight and rigid.

For the last almost exactly 100 years, we’ve had to alter our conception about what was fixed and what was flexed. As one scientist puts it, “There is but one absolute of unique significance, one truth that is independent of all other positions.”[2] The one fixed constant in the universe is the speed of light, and everything else is relative to it.

It’s my job to find spiritual truth in the midst of material fact, so here’s my Theory of Relativity for Christmas: my question is, In what way are you relative to the Light, the Light of the World, that is, the one fixed and faithful constant in a world at flux? What is your relationship to the Light, the one absolute of unique significance, the one truth independent of all frames of reference, the one Truth by which we measure the significance and successfulness and faithfulness of our lives?

Did you think once, like Jesus’ contemporaries that Rome’s reign would be eternal and that the Jerusalem Temple was indestructible? Did you think once that his humble, short, star-crossed life was trivial, but now somehow you’ve learned that it is the very point of human existence?

In an interview a while back the poet Maya Angelou (God rest her soul) was speaking of the confusion and futility of modern life, and she said that the malaise comes from our anchorlessness. We have fixed our lives to no reliable constant, and we have lost our way.   She says, “We have drifted into this never-never land, where we are up for grabs.”[3] Are you up for grabs? Or have you fixed your life relative to the Light?

Does it seem like many Americans are up for grabs these days? Muslim Americans are beginning to share some very important advice, online and at their mosques. Never stand at the edge of the subway platform, or at the ‘L’ station; stand far from the tracks with your back against the wall. After dark, walk in groups. Do not react if someone spits on you or tells you to go back to your country. When you dress in the morning, ask yourself if these are the kind of clothes you can run in, because you might have to. The windows of mosques should be covered with wire screens to prevent fire bombs. The doors should have bolts that can be locked from the inside, in case the ushers spot an armed assailant.[4]

At a prominent “Christian” college less than an hour away from here, a tenured political science professor was suspended because she had the audacity to suggest that Muslims and Christians worship the same God. How many gods does Wheaton College think there are? I thought they were monotheists.

We need more people who are relative to the Light, the Light of the World. Not necessarily those who call themselves by his name, but those who understood how he lived.

Albert and Elsa Einstein fled Berlin in 1933, shortly after Adolph Hitler became Chancellor, and moved to Princeton, New Jersey. Albert accepted an appointment at the Institute for Advanced Studies in Princeton. Five years later, in the fall of 1938, right around the time of Kristallnacht back in Germany, Princeton University gave a survey to its incoming a freshman class. One question on the survey asked “Who is the greatest living person in the world?” Albert Einstein came in second, perhaps because he was a local celebrity; everybody in Princeton knew Albert Einstein. Do you know who came in first? Adolph Hitler.[5]

One of the first people the Einsteins befriended in Princeton was a neighbor named Caroline Blackwood. In 1934, Mrs. Blackwood told Elsa Einstein that the Blackwoods would shortly be off to Palestine to see if they could help establish a homeland for the Jews who were becoming persona non grata in Germany and in Eastern Europe at that fraught time, 1934.

Elsa was surprised. She said, “Caroline, I didn’t know you were Jewish.” Mrs. Blackwood said, “Actually, we’re Presbyterian.” Elsa asked, “Then, why are you so interested in helping the Jews?” Mrs. Blackwood said, “There is an intimate and eternal connection between Christians and Jews. Jesus was a Jew, you know.” Elsa reached out to embrace Mrs. Blackwood. “No Christian has ever said that to me before in my life,” she said.[6]

It sounds as if Caroline Blackwood lived her life relative to the Light of the World. She was not up for grabs. His life is the one fixed and faithful constant in a world at flux.

He came down to a manger and went up to a cross; he turned water into wine and common fisherfolk into brave heroes; he made lame beggars walk and blind men see; he embraced the outcast and loved the unlovable and forgave the unforgivable and welcomed every other lost and lonely soul into his grace; and then he faced down the harrowing specter of cruel death and never turned aside. Are you up for grabs? Or is there some fixed constant that nothing in this world, literally nothing, not even your own survival, can tempt you to relinquish?

So, that’s my Theory of Relativity for Christmas.


[1]Walter Isaacson, Albert Einstein: His Life and Universe (New York: Simon & Schuster, 2007), p. 262.

[2]Arthur Zajonc, Catching the Light: The Entwined History of Light and Mind (New York: Oxford University Press, 1993), p. 262.

[3]Maya Angelou, in an interview with The Christian Science Monitor, “The Voice of a Writer in Process, David Hohnstrom, October 20, 1993.

[4]Kirk Semple, “‘I’m Frightened’: After Attacks in Paris, New York Muslims Cope With a Backlash,” The New York Times, November 26, 2015.

[5]Isaacson, 444-445.

[6]Isaacson, 433-434.