What the Bible says about Satan's Future Demise
(From Forerunner Commentary)
Their words plainly state that a set time—a future day—has already been appointed for their destruction, but meanwhile, they feared He would torment them. It seems they were attempting to quell their fear by reminding Him of this and delaying any punishment.
However, this is even more intriguing considering what Jesus says in Matthew 25:41, “Depart from Me, you cursed, into the everlasting fire prepared for the devil and his angels.” Indeed, Ezekiel 28:16-19 likewise portends a major disaster for the anointed cherub at some future time.
John W. Ritenbaugh
Do Angels Live Forever?