Horse
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.
Job 31:25-28
25
If I have rejoiced because my wealth was great, and because my hand had gotten much;
26
if I have seen the sun when it shined, or the moon moving in splendor,
27
and my heart has been secretly enticed, and my hand threw a kiss from my mouth,
28
this also would be an iniquity to be punished by the judges; for I should have denied the God who is above.