Arcana Coelestia # 8609
8609. 'And they took a stone' means the lowest level of God's truth. This is clear from the meaning of 'a stone' as truth, 643, 1298, 3720, 3769, 3771, 3789, 3798, 6426, in this instance the lowest level of truth since it was put underneath him and he sat on it. An ordinary stone furthermore means a lower level of truth, while a precious stone means a higher or more internal level of truth. What the lowest level of truth is becomes clear from what has been stated above in 8603 about the levels of truth that follow one another in order; that is to say, there are interior truths and exterior truths, the lowest of which are meant by the lowest level of truth.
Isaiah 14:21-23
21
Prepare for slaughter of his children because of the iniquity of their fathers, that they not rise up and possess the earth, and fill the surface of the world with cities.
22
"I will rise up against them," says Yahweh of Armies, "and cut off from Babylon name and remnant, and son and son's son," says Yahweh.
23
"I will also make it a possession for the porcupine, and pools of water. I will sweep it with the broom of destruction," says Yahweh of Armies.