Arcana Coelestia #486
486. Verse 4 And the days of Man after he beget Seth were eight hundred years; and he beget sons and daughters.
'Days' means periods of time and states in general. 'Years' means periods of time and states in particular. 'Sons and daughters' means the truths and goods that they perceived.
Jeremiah 13:3-7
3
The word of Yahweh came to me the second time, saying,
4
Take the belt that you have bought, which is on your waist, and arise, go to the Euphrates, and hide it there in a cleft of the rock.
5
So I went, and hid it by the Euphrates, as Yahweh commanded me.
6
It happened after many days, that Yahweh said to me, Arise, go to the Euphrates, and take the belt from there, which I commanded you to hide there.
7
Then I went to the Euphrates, and dug, and took the belt from the place where I had hidden it; and behold, the belt was marred, it was profitable for nothing.
