Charles Ellicott Commentary Luke 8:31

"And they entreated him that he would not command them to depart into the abyss." — Luke 8:31 (ASV)

To go out into the deep.—Better, into the abyss. The word is not found in the other Gospels, and it clearly means, not the deep waters of the Galilean lake, but the pit, the bottomless pit of Revelation 9:1-2; Revelation 9:11. The man, identifying himself with the demons, asks for any doom rather than that.