Apocalypse Revealed #448
448. And I heard the number of them. This symbolizes their character perceived, that it was as described hereafter.
To hear means, symbolically, to perceive. A number symbolizes the character of a thing or a state (nos. 10, 348, 364). It is the character of these people's state as described hereafter because that is what is now described in the following verses, which is why it begins, "And thus I saw."
Arcana Coelestia #9731
9731. 'And the net shall reach down to the middle of the altar' means the extent of the sensory perception. This is clear from the meaning of 'the net' as the level of sensory perception, dealt with above in 9726, the extent of it being meant by the requirement that it should reach down to the middle of the altar. It is not possible to supply an intelligible description of the arcanum implied by the words 'the extent of sensory perception' unless it is known that this kind of perception meant by 'a grating, a network' extends from a person's head down to the loins and comes to an end there. This extension is what the extension of the net down to the middle of the altar served to represent; for representatives on the natural level resemble the human form and have the same meaning as the parts of it they resemble, 9496. From the loins down however there is with a person a continuation of the kind of sensory perception that lies next within, and this continuation of that perception was represented by the general overlaying or covering round the altar with bronze, dealt with above in 9722.