So I wanted to tell a story
that really obsessed me when I was writing my new book,
and it's a story of something that happened
3,000 years ago,
when the Kingdom of Israel was in its infancy.
And it takes place in an area called the Shephelah
in what is now Israel.
And the reason the story obsessed me is that
I thought I understood it, and then I went back over it
and I realized that I didn't understand it at all.
Ancient Palestine had a -- along its eastern border,
there's a mountain range.
Still same is true of Israel today.
And in the mountain range are all of the ancient cities
of that region, so Jerusalem, Bethlehem, Hebron.
And then there's a coastal plain
along the Mediterranean, where Tel Aviv is now.
And connecting the mountain range with the coastal plain
is an area called the Shephelah,
which is a series of valleys and ridges that run east to west,
and you can follow the Shephelah, go through the Shephelah
to get from the coastal plain to the mountains.
And the Shephelah, if you've been to Israel, you'll know
it's just about the most beautiful part of Israel.
It's gorgeous, with forests of oak
and wheat fields and vineyards.
But more importantly, though, in the history of that region,
it's served, it's had a real strategic function,
and that is, it is the means by which hostile armies
on the coastal plain find their way,
get up into the mountains and threaten those living in the mountains.
And 3,000 years ago, that's exactly what happens.
The Philistines, who are the biggest of enemies
of the Kingdom of Israel,
are living in the coastal plain.
They're originally from Crete. They're a seafaring people.
And they may start to make their way
through one of the valleys of the Shephelah
up into the mountains,
because what they want to do is occupy the highland area
right by Bethlehem and split the Kingdom of Israel in two.
And the Kingdom of Israel, which is headed by King Saul,
obviously catches wind of this,
and Saul brings his army down from the mountains
and he confronts the Philistines in the Valley of Elah,
one of the most beautiful of the valleys of the Shephelah.
And the Israelites dig in along the northern ridge,
and the Philistines dig in along the southern ridge,
and the two armies just sit there for weeks
and stare at each other, because they're deadlocked.
Neither can attack the other, because to attack the other side
you've got to come down the mountain into the valley
and then up the other side, and you're completely exposed.
So finally, to break the deadlock,
the Philistines send their mightiest warrior
down into the valley floor, and he calls out
and he says to the Israelites,
"Send your mightiest warrior down,
and we'll have this out, just the two of us."
This was a tradition in ancient warfare called single combat.
It was a way of settling disputes
without incurring the bloodshed of a major battle.
And the Philistine who is sent down,
their mighty warrior, is a giant.
He's 6 foot 9.
He's outfitted head to toe in this glittering bronze armor,
and he's got a sword and he's got a javelin
and he's got his spear. He is absolutely terrifying.
And he's so terrifying that none of the Israelite soldiers want to fight him.
It's a death wish, right? There's no way they think they can take him.
And finally the only person who will come forward
is this young shepherd boy,
and he goes up to Saul and he says, "I'll fight him."
And Saul says, "You can't fight him. That's ridiculous.
You're this kid. This is this mighty warrior."
But the shepherd is adamant. He says, "No, no, no,
you don't understand, I have been defending my flock
against lions and wolves for years. I think I can do it."
And Saul has no choice. He's got no one else who's come forward.
So he says, "All right."
And then he turns to the kid, and he says,
"But you've got to wear this armor. You can't go as you are."
So he tries to give the shepherd his armor,
and the shepherd says, "No."
He says, "I can't wear this stuff."
The Biblical verse is, "I cannot wear this for I have not proved it,"
meaning, "I've never worn armor before. You've got to be crazy."
So he reaches down instead on the ground
and picks up five stones
and puts them in his shepherd's bag
and starts to walk down the mountainside to meet the giant.
And the giant sees this figure approaching,
and calls out, "Come to me so I can feed your flesh
to the birds of the heavens and the beasts of the field."
He issues this kind of taunt towards this person
coming to fight him.
And the shepherd draws closer and closer,
and the giant sees that he's carrying a staff.
That's all he's carrying.
Instead of a weapon, just this shepherd's staff,
and he says -- he's insulted --
"Am I a dog that you would come to me with sticks?"
And the shepherd boy takes one of his stones
out of his pocket, puts it in his sling
and rolls it around and lets it fly
and it hits the giant right between the eyes --
right here, in his most vulnerable spot --
and he falls down either dead or unconscious,
and the shepherd boy runs up and takes his sword
and cuts off his head,
and the Philistines see this and they turn and they just run.
And of course, the name of the giant is Goliath
and the name of the shepherd boy is David,
and the reason that story has obsessed me
over the course of writing my book
is that everything I thought I knew about that story
turned out to be wrong.
So David, in that story, is supposed to be the underdog, right?
In fact, that term, David and Goliath,
has entered our language as a metaphor for
improbable victories
by some weak party over someone far stronger.
Now why do we call David an underdog?
Well, we call him an underdog because he's a kid,
a little kid, and Goliath is this big, strong giant.
We also call him an underdog
because Goliath is an experienced warrior,
and David is just a shepherd.
But most importantly, we call him an underdog
because all he has is -- it's that Goliath is outfitted with
all of this modern weaponry,
this glittering coat of armor
and a sword and a javelin and a spear,
and all David has is this sling.
Well, let's start there with the phrase
"All David has is this sling,"
because that's the first mistake that we make.
In ancient warfare, there are three kinds of warriors.
There's cavalry, men on horseback and with chariots.
There's heavy infantry, which are foot soldiers,
armed foot soldiers with swords and shields
and some kind of armor.
And there's artillery, and artillery are archers,
but, more importantly, slingers.
And a slinger is someone who has a leather pouch
with two long cords attached to it,
and they put a projectile, either a rock or a lead ball,
inside the pouch, and they whirl it around like this
and they let one of the cords go,
and the effect is to send the projectile forward
towards its target.
That's what David has, and it's important to understand
that that sling is not a slingshot.
It's not this, right? It's not a child's toy.
It's in fact an incredibly devastating weapon.
When David rolls it around like this,
he's turning the sling around probably
at six or seven revolutions per second,
and that means that when the rock is released,
it's going forward really fast,
probably 35 meters per second.
That's substantially faster than a baseball
thrown by even the finest of baseball pitchers.
More than that, the stones in the Valley of Elah
were not normal rocks. They were barium sulphate,
which are rocks twice the density of normal stones.
If you do the calculations on the ballistics,
on the stopping power of the rock fired from David's sling,
it's roughly equal to the stopping power
of a [.45 caliber] handgun.
This is an incredibly devastating weapon.
Accuracy, we know from historical records
that slingers -- experienced slingers could hit
and maim or even kill a target at distances of up to 200 yards.
From medieval tapestries, we know that slingers
were capable of hitting birds in flight.
They were incredibly accurate.
When David lines up -- and he's not 200 yards away from Goliath,
he's quite close to Goliath --
when he lines up and fires that thing at Goliath,
he has every intention and every expectation
of being able to hit Goliath at his most vulnerable spot
between his eyes.
If you go back over the history of ancient warfare,
you will find time and time again
that slingers were the decisive factor against infantry
in one kind of battle or another.
So what's Goliath? He's heavy infantry,
and his expectation when he challenges the Israelites to a duel
is that he's going to be fighting another heavy infantryman.
When he says, "Come to me that I might
feed your flesh to the birds of the heavens and the beasts of the field,"
the key phrase is "Come to me."
Come up to me because we're going to fight,
hand to hand, like this.
Saul has the same expectation.
David says, "I want to fight Goliath,"
and Saul tries to give him his armor,
because Saul is thinking, "Oh, when you say 'fight Goliath,'
you mean 'fight him in hand-to-hand combat,'
infantry on infantry."
But David has absolutely no expectation.
He's not going to fight him that way. Why would he?
He's a shepherd. He's spent his entire career
using a sling to defend his flock against lions and wolves.
That's where his strength lies.
So here he is, this shepherd, experienced
in the use of a devastating weapon,
up against this lumbering giant
weighed down by a hundred pounds of armor
and these incredibly heavy weapons
that are useful only in short-range combat.
Goliath is a sitting duck. He doesn't have a chance.
So why do we keep calling David an underdog,
and why do we keep referring to his victory as improbable?
There's a second piece of this that's important.
It's not just that we misunderstand David
and his choice of weaponry.
It's also that we profoundly misunderstand Goliath.
Goliath is not what he seems to be.
There's all kinds of hints of this in the Biblical text,
things that are in retrospect quite puzzling
and don't square with his image as this mighty warrior.
So to begin with, the Bible says that Goliath
is led onto the valley floor by an attendant.
Now that is weird, right?
Here is this mighty warrior
challenging the Israelites to one-on-one combat.
Why is he being led by the hand
by some young boy, presumably,
to the point of combat?
Secondly, the Bible story makes special note
of how slowly Goliath moves,
another odd thing to say when you're describing
the mightiest warrior known to man at that point.
And then there's this whole weird thing
about how long it takes Goliath to react
to the sight of David.
So David's coming down the mountain,
and he's clearly not preparing for hand-to-hand combat.
There is nothing about him that says,
"I am about to fight you like this."
He's not even carrying a sword.
Why does Goliath not react to that?
It's as if he's oblivious to what's going on that day.
And then there's that strange comment he makes to David:
"Am I a dog that you should come to me with sticks?"
Sticks? David only has one stick.
Well, it turns out that there's been a great deal
of speculation within the medical community over the years
about whether there is something
fundamentally wrong with Goliath,
an attempt to make sense of all of those apparent anomalies.
There have been many articles written.
The first one was in 1960 in the Indiana Medical Journal,
and it started a chain of speculation
that starts with an explanation for Goliath's height.
So Goliath is head and shoulders above
all of his peers in that era,
and usually when someone is that far out of the norm,
there's an explanation for it.
So the most common form of giantism
is a condition called acromegaly,
and acromegaly is caused by a benign tumor
on your pituitary gland
that causes an overproduction of human growth hormone.
And throughout history, many of the most famous giants
have all had acromegaly.
So the tallest person of all time
was a guy named Robert Wadlow
who was still growing when he died at the age of 24
and he was 8 foot 11.
He had acromegaly.
Do you remember the wrestler André the Giant?
Famous. He had acromegaly.
There's even speculation that Abraham Lincoln had acromegaly.
Anyone who's unusually tall,
that's the first explanation we come up with.
And acromegaly has a very distinct set of side effects
associated with it,
principally having to do with vision.
The pituitary tumor, as it grows,
often starts to compress the visual nerves in your brain,
with the result that people with acromegaly
have either double vision or they are profoundly nearsighted.
So when people have started to speculate
about what might have been wrong with Goliath,
they've said, "Wait a minute,
he looks and sounds an awful lot like someone
who has acromegaly."
And that would also explain so much of what was strange
about his behavior that day.
Why does he move so slowly
and have to be escorted down into the valley floor
by an attendant?
Because he can't make his way on his own.
Why is he so strangely oblivious to David
that he doesn't understand that David's not going to fight him
until the very last moment?
Because he can't see him.
When he says, "Come to me that I might feed your flesh
to the birds of the heavens and the beasts of the field,"
the phrase "come to me" is a hint also of his vulnerability.
Come to me because I can't see you.
And then there's, "Am I a dog that you should come to me with sticks?"
He sees two sticks when David has only one.
So the Israelites up on the mountain ridge
looking down on him thought he was
this extraordinarily powerful foe.
What they didn't understand was that
the very thing that was the source of his apparent strength
was also the source of his greatest weakness.
And there is, I think, in that,
a very important lesson for all of us.
Giants are not as strong and powerful as they seem.
And sometimes the shepherd boy has a sling in his pocket.
Thank you.
(Applause)