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.

3750. What kind of idea about heaven those people have who, superior to all others, are thought to be in communication with heaven and to be under its influence has also been shown to me visually. Appearing overhead are those who in the world wished to be worshipped as gods and with whom self-love had been raised up as far as it could possibly go as they rose up in the hierarchy and acquired the supposed liberty that went with such powerful positions. At the same time those people are deceitful, acting under a presence of innocence and of love to the Lord. Their appearance on high overhead is the result of a delusion about height; but in fact they are underfoot in hell.

[2] One of them brought himself down to me, who, I was told by others, had been Pope when in the world. He spoke to me very courteously, first of all about Peter and his keys which he imagined that he had held. But when I asked him about the power of letting into heaven whomever he liked he had so crude an idea about heaven that he represented it as a door through which entrance was gained. He said that he opened the door to the poor for nothing, but that the rich were assessed according to their means, and that what they gave was holy. I asked whether he believed that those he let in remained there. He said that he did not know; if they did not, then they went away. I went on to say that he could not know those persons interiorly - whether they were worthy persons or possibly robbers who should be in hell. He said that this was no concern of his; if they were not worthy they could be sent away. But he was told what was meant by Peter's keys, namely faith rooted in love and charity; and because the Lord alone confers such faith the Lord alone is the one who lets people into heaven. He was also told that Peter does not appear to anyone but is a simple ordinary spirit who has no more power than anyone else. Concerning the Lord this former Pope held no other opinion than that He ought to be worshipped insofar as He confers such power; and that if He did not confer it, he thought - as I perceived - that He ought not to be worshipped any longer. I then went on to talk to him about the internal man, of which he had a foul idea.

[3] I was shown visually the nature of the freedom, fullness, and delight of the respiration he enjoyed when seated on his throne in his consistory and believed that he spoke under the influence of the Holy Spirit. He was taken back into a similar state he had passed through there - for in the next life anyone can be taken back without difficulty into the state of life which he had passed through in the world, because the state of his life remains with him after death - and the nature of his respiration in that state was conveyed to me. It was free and attended with delight, slow, regular, deep, and filling the whole breast. But when he was contradicted there was in the abdomen, into which his respiration extended, something that seemed to be turning over and crawling about. And when he imagined that what he pronounced was Divine he perceived it from his respiration, which was more soundless and so to speak in harmony with it.

[4] I was then shown who the spirits are who direct Popes like this one, namely the horde of sirens overhead who have acquired that disposition and life by which they worm their way into every kind of affection with the intention of ruling over others and subjecting them to themselves, and of destroying for selfish reasons whomever they can, employing holiness and innocence as the means. They fear for themselves and so act cautiously; but given the opportunity they plunge for selfish reasons into merciless acts of cruelty.