615. And like the voice of loud thunder. This symbolizes the Lord speaking through the new heaven out of Divine love.

Lightnings, thunderings and voices symbolize enlightenment, perception and instruction, as may be seen in no. 236. And seven thunders speaking symbolize the Lord's speaking through the whole of heaven (no. 472).

When the Lord speaks through heaven, He does so from the third heaven through the second heaven, thus from love through Divine wisdom, for the third heaven is impelled by His Divine love, and the second heaven by His Divine wisdom. The Lord never speaks in any other way when He speaks from the higher heavens. This, then, is what is meant by a voice like the voice of many waters, and by a voice like the voice of loud thunder. Many waters are the Divine truths of Divine wisdom, and loud thunder is the Divine goodness of Divine love.

It's common to say “I see” when we understand something. And indeed, “seeing” in the Bible represents grasping and understanding spiritual things. So it makes sense that the eyes, which allow us to see, represent the intellect, which allows us to understand spiritual things. This can also be used in the negative, of course; the Bible speaks of people having eyes and refusing to see, and the Lord when He was in the world advised plucking out an offending eye. These represent a refusal to acknowledge truth, or being misled by falsity.