How did the legion of demons know that Jesus would torture them one of these days?

[tonychanyt]

Isaiah prophesied in 24:

21 In that day the LORD will punish the host of heaven above and the kings of the earth below. 22 They will be gathered together like prisoners in a pit. They will be confined to a dungeon and punished after many days.

2Pe 2:

4b God did not spare the angels when they sinned, but cast them deep into Tartarus, placing them in chains of darkness to be held for judgment.

Jude 1:

6 And the angels who did not stay within their own domain but abandoned their proper dwelling—these He has kept in eternal chains under darkness, bound for judgment on that great day.

Rebellious heavenly beings will be imprisoned, judged, and punished.

Now, Mt 8:

28 When Jesus arrived on the other side in the region of the Gadarenes, He was met by two demon-possessed men coming from the tombs. They were so violent that no one could pass that way.
29 “What do You want with us, Son of God?” they shouted. “Have You come here to torture us before the appointed time?”

Mk 5:9 called this group of demons Legion. They knew that one day Jesus would torture them—probably on his second coming. They worried that Jesus might do it to them on his first coming, that he might send them to the Tartarus dungeon to torture them right away.

How did they know about their eventual ending?

Isaiah hinted at them. Further, as spiritual beings, God probably had warned them before in the spiritual realm.

Later, Jesus made it explicit in Matthew 25:

41 “Then he will say to those on his left, ‘Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels."

They knew what was coming to them.