426. As regards 'iron' meaning natural truth, this is clear from the places quoted already, and from the following as well: In Ezekiel in reference to Tyre,

Tarshish was your trader because of the vastness of all your wealth - in silver, iron, tin, and lead they provided Your wares. Dan and Javan, and Meusal, exchanged wrought iron in your tradings; cassia and calamus were in your market. Ezekiel 27:12, 19.

From these verses, and from those before and after them in the same chapter, it is quite clear that celestial and spiritual riches are meant. Each commodity, and also each name mentioned there, has some specific meaning, for the Word of the Lord is spiritual and not just verbal in content.

[2] In Jeremiah,

Can one smash iron, iron from the north, and bronze? Your resources and your treasures I will give as spoil, without price, even for all your sins. Jeremiah 15:12-13.

Here 'iron' and 'bronze' stand for natural truth and good. 'That which comes from the north' means that which is sensory and natural, for natural in comparison with spiritual and celestial is as thick darkness or the north to light or the south. The natural also resembles shade, which is also the meaning here of 'Zillah' who was the mother. It is also quite plain that 'resources and treasures' are celestial and spiritual riches.

[3] In Ezekiel,

Take an iron pan and place it as an iron wall between you and the city, and set your face ¹ towards it, and let it be in a state of siege, and oppress it. Ezekiel 4:3.

Here too it is clear that 'iron' means truth. Great strength is attributed to truth because nothing is able to withstand it. This in addition is why iron, which means truth, that is, the truth of faith, is referred to as smashing and crushing to pieces, as in Daniel 2:33, 40. And in John,

He who overcomes, to him will I give power over the nations to rule ² them with an iron rod as when earthen pots are broken in pieces. Revelation 2:26-27.

In the same author,

The woman gave birth to a male child, who was to rule ² all nations with an iron rod. Revelation 12:5.

[4] The explanation appears in John that an 'iron rod' means truth which belongs to the Word of the Lord,

I saw heaven opened, when behold, a white horse! And He who sat upon it was called faithful and true, and in righteousness He judges and fights. He was clothed in a robe dipped in blood and His name is called the Word of God. From His mouth issues a sharp sword, and with it He will smite the nations, and will rule ² them with an iron rod. Revelation 19, 11, 13, 15.

Footnotes:

Intellectual things -- ideas, knowledge, facts, even insight and understanding -- are more separate and free-standing than emotional things, and it's easier to imagine numbering them as individual things. Our loves and affections tend to be more amorphous -- they can certainly be powerful, but would be harder to measure. Using words like “much,” “many,” myriad” and “multitude” to describe a collection of things gives the sense that there is an exact number, even if we don't know what it is and don't want to bother trying to count. These words, then, are used in the Bible in reference to intellectual things -- our thoughts, knowledge and concepts. Words that indicate largeness without the idea of number -- “great” is a common one -- generally refer to loves, affections and the desire for good. Here's one way to think about this: Say you want to take some food to a friend who just had a baby. That's a desire for good (assuming you're doing it from genuinely good motives). To actually do it, though, takes dozens of thoughts, ideas, facts and knowledges. What does she like to eat? What do you have to cook? What do you cook well? Can you keep it hot getting to her house? Is it nutritious? Does she have any allergies? So one good desire can bring a multitude of ideas into play.