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.

3356. The reason 'a quake' means an alteration of state is that a quake occurs within the space-time continuum, and in the next life there is no concept of space and time, but instead of these the concept of state. In the next life it does indeed appear as though all things exist within space and follow one another in a time-sequence, but in themselves they are alterations of state, for space and time there are the products of these. This is very well known to all spirits, even evil ones, who by means of alterations of state effected in others cause them to appear somewhere other than where they in fact are. Man too is able to know of this from the fact that insofar as his state is one of affection and therefore of joy, or insofar as it is one of thought and therefore of withdrawal from the body, he is outside time. For while such a state lasts, many hours seem to him to be as scarcely one hour. The reason for this is that states belong to his internal man, which is his spirit, to which states intervals of space and periods of time in the external man correspond. 'A quake' therefore, being one of the consecutive events that occur within space and time, in the internal sense means an alteration of state.