Satan may have been cast down to Hell; he may have been plunged into the burning lake by the heavenly host. But he's still his old, defiant self. Far from being chastened by his expulsion from Heaven, Satan is, if anything, more emboldened than ever before to challenge the Almighty.
Arising from the burning lake of Hell, Satan looks more like a noble Greek warrior than a fallen angel. And that's entirely appropriate, because the Prince of Darkness is in a fighting mood, determined to hit back at God for casting him down.
Now that Satan has emerged from the burning lake, it's time to rouse his acolytes, the other fallen angels cast down with him from Heaven, to action. Addressing his followers, Satan commands them to
Awake, arise, or be forever fallen!
In other words, if they don't stand up to God, if they don't challenge what Satan regards as his tyrannical rule, then they will remain fallen for the rest of eternity.
Hell is not a place of slumber, as in “the vales of Heaven.” It is a place where the fallen angels must come together as one and plan to get back at God for what he's done to them. Among other things, this means adopting the same proud, defiant posture of Satan as he emerges, head held high, from the burning lake of Hell.