בס״ד

Kavanot: פרשת עקב תשפ״ד

Thoughts on Tanach and the Davening

This week’s parsha includes one of my favorite psukim:

ארץ אשר לא במסכנת תאכל בה לחם לא תחסר כל בה; ארץ אשר אבניה ברזל ומהרריה תחצב נחשת׃

דברים ח:ט

I like it because I like thinking about the history of technology. I’m going to talk about bronze and iron, and iron from rocks and bronze from hills.

We mentioned technology in last week’s shiur:

ותקח צפרה צר ותכרת את ערלת בנה ותגע לרגליו; ותאמר כי חתן דמים אתה לי׃

שמות ד:כה

Tziporah’s kitchen knives were sharp rocks. But people had already discovered that there were shiny rocks (or rocks with shiny parts) that you could heat and melt into metals like copper and tin, and that you could mix those metals into alloys that were even harder and stronger, into things like bronze, and you could kill lots of people with it. Technology is always driven by the ability to kill lots of people; that’s how we name “The Ages of Man”: Stone Age, Bronze Age, Iron Age, Nuclear Age.

Weapons cause technological development

Adapted from SMBC, 2011-01-28

So everyone wanted to dig into the ground and find those shiny rocks and make bronze. The time period of יציאת מצרים, when the Torah was given, was the late Bronze Age.

But iron is even better than bronze. It can be cast or forged and holds an edge well, and even more important, iron is everywhere. It’s the most abundant heavy element on the planet; in fact, it’s the most abudant heavy element in the solar system.

We need to take a detour into nuclear physics. Iron is the most stable element in terms of nuclear physics

Light elements such as hydrogen release large amounts of energy (a big increase in binding energy) when combined to form heavier nuclei. Conversely, heavy elements such as uranium release energy when converted to lighter nuclei through alpha decay and nuclear fission.

Wikipedia, Iron peak

You might think of the situation like this: all smaller nuclei want to “grow up” to be like iron, and they are willing to pay (produce energy) to move toward that goal. But iron is a mature nucleus with good self-esteem, perfectly content being iron; it requires payment (must absorb energy) to change its stable nuclear structure. This is the exact opposite of what has happened in each nuclear reaction so far: instead of providing energy to balance the inward pull of gravity, any nuclear reactions involving iron would remove some energy from the core of the star.

OpenStax, Evolution of Massive Stars—An Explosive Finish

Our Sun is a second- or third-generation star. All the rocky and metalic material we stand on, the iron in our blood…were produced billions of years ago in the interior of a red giant star. We are made of star-stuff.

Carl Sagan, The Cosmic Connection, cited in Quote Investigator, We Are Made of Star-Stuff

Iron is the most stable element in terms of nuclear physics, so lots of it is made as stars run through their fusion cycle. So iron should be cheap. Why was there a Bronze Age at all? That is because you can mine copper and tin, but you can’t mine iron. Iron nuclei may be very stable, but iron atoms with their electrons are very chemically reactive, and they bind to oxygen, forming rust. Copper and tin oxidize in a thin outer layer that protects the rest of the metal, but iron oxide is porous enough that it will rust through.

You can’t dig up pure iron out of the ground. Instead, what you find is an oxidized form of the metal called ore. A common form of iron ore looks like red, rusty dirt—in fact, ore is chemically basically the same thing as rust…To get any metal out of its ore, you have to separate the elemental metal from the oxygen, by heating it in a furnace at thousands of degrees, a process called smelting.

Jason Crawford, Iron: From Mythical to Mundane

So you can’t get an Iron Age until you invent iron smelting technology. That won’t happen until the time of דוד המלך. That’s how I understand the war with the פלשתים:

יט וחרש לא ימצא בכל ארץ ישראל; כי אמרו פלשתים פן יעשו העברים חרב או חנית׃ כ וירדו כל ישראל הפלשתים ללטוש איש את מַחֲרַשְׁתּוֹ ואת אתו ואת קרדמו ואת מַחֲרֵשָׁתוֹ׃

שמואל א פרק יג

וחרש: אומן ברזל.

מצודת ציון, שמואל א יג:יט

The פלשתים had military technology that בני ישראל lacked.


So I’m claiming that, at the time the Torah was written, no one could use iron. But I’m clearly wrong; our pasuk mentions it explicitly—ארץ אשר אבניה ברזל! And the Midyanites had iron weapons:

כב אך את הזהב ואת הכסף; את הנחשת את הברזל את הבדיל ואת העפרת׃ כג כל דבר אשר יבא באש תעבירו באש וטהר אך במי נדה יתחטא; וכל אשר לא יבא באש תעבירו במים׃

במדבר פרק לא

And iron-based weapon technology goes back even further than that:

וצלה גם הוא ילדה את תובל קין לטש כל חרש נחשת וברזל; ואחות תובל קין נעמה׃

בראשית ד:כב

תובל קין: תובל אמנתו של קין, תובל לשון תבלין, תבל והתקין אמנותו של קין לעשות כלי זין לרוצחים.

רש״י, בראשית ד:כב

The answer is, of course, that the problem with iron is that it reacts with oxygen. Just find iron that’s not exposed to oxygen and you can use that. The solar system is full of iron rocks; just get in your Bronze-Age spaceship, grab a small asteroid, and you have enough iron to conquer an empire!

That may not be that easy, but fortunately, sometimes, the asteroids come to Earth by themselves.

It was easier to believe that two Yankee professors could lie than to admit that stones could fall from heaven.

Attributed to Thomas Jefferson, from Erik Ofgang, In December 1807, a Meteorite Fell From the Sky Above Connecticut and Into Scientific History

The thing about meteoric iron is that it is relatively high in nickel, another stable star-stuff metal that is very common in the solar system. Smelting separates the metals. Archeologists can tell the difference.

The study of meteoritic irons, Bronze Age iron artifacts and ancient terrestrial irons permit us to validate this chemical approach. The major interest is that non-invasive p-XRF analyses provide reliable Fe:Co:Ni abundances, without the need to remove a sample; they can be performed in situ, in the museums where the artifacts are preserved. The few iron objects from the Bronze Age sensu stricto that could be analyzed are definitely made of meteoritic iron.

Albert Jambon, Bronze Age Iron: Meteoritic or Not? A Chemical Strategy

So, bottom line: when Moshe tells us that Israel is ארץ אשר אבניה ברזל ומהרריה תחצב נחשת, he means literally that iron comes from the rocks, and copper from the mines.


I think that’s incredibly cool. But I’m wrong.

ברזל מעפר יקח; ואבן יצוק נחושה׃

איוב כח:ב

“Iron is taken out of the earth”! And ספר איוב was written by Moshe himself, so maybe our pasuk shouldn’t be read as sharply as I have.

משה כתב ספרו ופרשת בלעם ואיוב.

בבא בתרא יד,ב

But I think it still reflects the technological reality. This perek of איוב is a metaphor:

ויסף איוב שאת משלו; ויאמר׃

איוב כז:א

And we need to look at it in context:

א כי יש לכסף מוצא; ומקום לזהב יזקו׃ ב ברזל מעפר יקח; ואבן יצוק נחושה׃ ג קץ שם לחשך ולכל תכלית הוא חוקר; אבן אפל וצלמות׃… ה ארץ ממנה יצא לחם; ותחתיה נהפך כמו אש׃… י בצורות יארים בקע; וכל יקר ראתה עינו׃ יא מבכי נהרות חבש; ותעלמה יצא אור׃

איוב פרק כח

It’s a metaphor for strip mining, tearing away the earth to find the treasures hidden within.

יב והחכמה מאין תמצא; ואי זה מקום בינה׃ יג לא ידע אנוש ערכה; ולא תמצא בארץ החיים׃… כ והחכמה מאין תבוא; ואי זה מקום בינה׃ כא ונעלמה מעיני כל חי; ומעוף השמים נסתרה׃… כג אלקים הבין דרכה; והוא ידע את מקומה׃… כז אז ראה ויספרה; הכינה וגם חקרה׃ כח ויאמר לאדם הן יראת אדנ־י היא חכמה; וסור מרע בינה׃

איוב פרק כח

So the force of איוב's משל is that even if you could mine iron from the earth and overturn the mountains, you would not find wisdom. That comes from יראת ה׳.

And that is the message of our parsha as well. Moshe isn’t me, isn’t really interested in military technology. The point of ארץ אשר אבניה ברזל ומהרריה תחצב נחשת come at the beginning of the paragraph:

ב וזכרת את כל הדרך אשר הוליכך ה׳ אלקיך זה ארבעים שנה במדבר; למען ענתך לנסתך לדעת את אשר בלבבך התשמר מצותיו אם לא׃ ג ויענך וירעבך ויאכלך את המן אשר לא ידעת ולא ידעון אבתיך; למען הודיעך כי לא על הלחם לבדו יחיה האדם כי על כל מוצא פי ה׳ יחיה האדם׃

דברים פרק ח

And so, for all the high technology you will develop in ארץ ישראל, you need to remember:

ואכלת ושבעת וברכת את ה׳ אלקיך על הארץ הטבה אשר נתן לך׃

דברים ח:י