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.

2623. 'A son' means the Divine Rational. This is clear from the meaning of 'a son'. In the internal sense of the Word 'a son' means truth, 489, 491, 533; and because truth is the principal element in the rational, 2072, 2189, 'a son' also means the rational. But here the Divine Rational is meant in which the principal element is good. 'Isaac' too, to whom 'a son' refers, represents this good, as will be shown further on.