In Ezekiel 26:11, this signifies the love of learning or intellectual things. (Arcana Coelestia 3727)

In Revelation 6:2, this signifies the love of understanding the Word. (Apocalypse Revealed 298)

In Zechariah 12:4, this signifies that the intellectual should be filled with falsities. (Arcana Coelestia 2383[2])

In general, 'a horse' signifies knowledge or understanding of the Word. In an opposite sense it signifies the understanding of the Word falsified by reasonings, and likewise destroyed from self-derived intelligence. 'A dead horse' signifies no understanding of truth from the Word.

3727. As regards the meaning of 'a pillar', the reason why it means a holy boundary and so the ultimate degree of order is that in most ancient times people used to place stones where their boundaries ran which separated one person's property or inheritance from another's. These served as a sign and witness to the existence of the boundaries there. The most ancient people, who in every object and in every pillar thought of something celestial or spiritual, 1977, 2995, thought, when they saw these stones set up as pillars, of the ultimate things present in man, and so of the ultimate degree of order, which is truth in the natural man. And it was from those most ancient people who lived before the Flood that the ancients who lived after it acquired this custom, 920, 1409, 2179, 2896, 2897, and began to regard the stones they set up on their boundaries as sacred, for the reason, as stated, that they meant holy truth as it exists in the ultimate degree of order, and also called those stones 'pillars'. This was how it came about that pillars were introduced into their worship, and why they erected them where they had their sacred groves and subsequently their temples, and also anointed them with oil, a point to be dealt with shortly. Indeed the worship of the Ancient Church consisted of things that had been perceived and things that had carried a meaning among the most ancient people prior to the Flood, as is evident from the paragraphs that have just been referred to. Since the most ancient people talked to angels and were in their company while still on earth, they received it from heaven that 'stones' means truth and 'wood' good; see just above in 3720. This then is why 'pillars' means a holy boundary, and so truth as it exists in the ultimate degree of order with man. For good which flows in from the Lord by way of the internal man terminates in the external man, and in the truth that is there. Man's thought, speech, and activity, which are the ultimates of order, are nothing else than truths stemming from good. In fact they are the images or forms which good takes, for they belong to the understanding part of the human mind, whereas the good that is within them, and from which they spring, belongs to the will part.

[2] The fact that pillars were erected as a sign and a witness, and were also introduced into worship, and that in the internal sense they mean a holy boundary, or truth within man's natural, which is the ultimate degree of order, becomes clear from other places in the Word, as in the following verses where the subject is the covenant made between Laban and Jacob,

Now come, let us make a covenant, I and you, and let it be a witness between me and you. And Jacob took a stone and erected it as a pillar. Laban said to Jacob, Behold this heap, and behold the pillar which I have erected between me and you. This heap is a witness and the pillar is a witness, that I will not pass beyond this heap to you, and that you will not pass beyond this heap and this pillar to me, to do harm. Genesis 31:44-45, 51-52.

Here 'pillar' means truth, as will be seen in the explanation of those verses.

[3] In Isaiah,

On that day there will be five cities in the land of Egypt which speak with the lips of Canaan and swear to Jehovah Zebaoth. On that day there will be an altar to Jehovah in the midst of the land of Egypt, and a pillar at its border to Jehovah, which will be a sign and a witness to Jehovah Zebaoth in the land of Egypt. Isaiah 19:18-20.

'Egypt' stands for facts which belong to the natural man, 'an altar' for Divine worship in general, for in the second Ancient Church that began with Eber the altar became the first and foremost representative in its worship, 921, 1343, 2777, 2811. 'The midst of the land of Egypt' stands for the primary and inmost aspect of worship, 2940, 2973, 3436. 'Pillar' stands for truth as it exists in the ultimate degree of order in the natural. The fact that it stood at the border as a sign and a witness is quite evident.

[4] In Moses,

Moses wrote down all the words of Jehovah and rose up in the morning and built an altar beside Mount Sinai, and twelve pillars for the twelve tribes of Israel. Exodus 24:4.

Here similarly 'an altar' was the representative of all worship, and indeed was the representative of good present in worship. 'The twelve pillars' however were the representative in worship of truth that stems from good - 'twelve' meaning every aspect of truth in its entirety, see 577, 2089, 2129 (end), 2130 (end), 3272; and the twelve tribes likewise meaning every aspect of truth in the Church, as in the Lord's Divine mercy will be shown in the next chapter.

[5] Because altars were representative of all good in worship, and the Jewish Church was established so as to represent the celestial Church which acknowledged no other truth than truth stemming from good, which is called celestial truth (for the celestial Church was totally unwilling to separate truth from good, so much so that it was unwilling even to refer to anything of faith or truth without thinking about good, and doing so from good, see 202, 337, 2069, 2715, 2718, 3246), truth was therefore represented by the stones of the altar. And they were forbidden to represent it by means of pillars lest in so doing they separated truth from good and by representation worshipped truth instead of good. This accounts for the following prohibition in Moses,

You shall not plant for yourself a grove of any kind of tree beside the altar of Jehovah your God which you shall make for yourself. And you shall not erect for yourself a pillar, which Jehovah your God hates. Deuteronomy 16:21-22.

For worshipping truth separated from good, or faith separated from charity, is contrary to the Divine since it is contrary to order, meant by 'you shall not erect for yourself a pillar, which Jehovah your God hates'.

[6] Despite this they did erect them and so represented things that are contrary to order, as is clear in Hosea,

Israel, according to the multiplying of his fruit, multiplies altars; according to the goodness of their land they make well their pillars. But He will overturn their altars, and lay waste their pillars. Hosea 10:1-2.

In the first Book of Kings,

Judah did what was evil in the eyes of Jehovah, and they built for themselves high places and pillars and groves on every high hill, and under every green tree. 1 Kings 14:22-23.

In the second Book of Kings,

The children of Israel set up pillars for themselves and groves on every high hill and under every green tree. 2 Kings 17:10.

In the same book,

Hezekiah removed the high places, and broke down the pillars, and cut down the grove, and smashed the bronze snake which Moses had made, because they had been burning incense to it. 2 Kings 18:4.

[7] Since gentile nations too derived through tradition the idea that the holiness of worship was to be represented by means of altars and pillars, and yet they were under the influence of evil and falsity, the altars among the nations therefore mean the evils of worship and the pillars the falsities. This was why the command was given for them to be destroyed. In Moses,

The altars of the nations you shall overthrow, and you shall break down their pillars and tear down their groves. Exodus 34:13; Deuteronomy 7:5; 12:3.

In the same author,

You shall not bow down to the gods of the nations, or worship them, or do according to their works, for you shall utterly destroy them, and utterly break down their pillars. Exodus 23:24.

'The gods of the nations' stands for falsities, 'their works' for evils, 'breaking down their pillars' for destroying worship arising out of falsity.

[8] In Jeremiah,

Nebuchadnezzar king of Babel will break down the pillars of the house of the sun that is in the land of Egypt, and the houses of the gods of Egypt he will burn with fire. Jeremiah 43:13.

In Ezekiel,

By means of the hoofs of his horses Nebuchadnezzar king of Babel will trample all your streets, slay the people with the sword, and cause your mighty pillars to come down to the ground. Ezekiel 26:11.

This refers to Tyre. 'Nebuchadnezzar king of Babel' stands for that which lays waste, 1327 (end). 'The hoofs of horses' stands for the lowest form of intellectual concepts, such as facts based on mere sensory impressions - 'hoofs' meaning lowest concepts, as will in the Lord's Divine mercy be confirmed elsewhere. 'Horses' stands for matters of the understanding, 2760-2762, 'streets' for truths, and in the contrary sense for falsities, 2336. 'trampling' on them is destroying cognitions of truth, which are meant by 'Tyre' - 'Tyre', the subject here, meaning cognitions of truth, 1201. 'Slaying the people with the sword' stands for destroying truths by means of falsity - 'people' being used in reference to truths, 1259, 1260, 3295, 3581, and 'sword' meaning falsity engaged in conflict, 2799. From this one may see what 'causing your mighty pillars to come down to the ground' means - 'might' being used in reference either to truth or to falsity, as is also clear from the Word.