Lucifer is the spirit of intellect, the light bringer, who, who's flown too high and challenges God himself, and falls. And in Milton story, Lucifer is called on his pretension by God... He's a symbol of intellect, that in combination with the notion that he's a Lightbringer, it's a symbol of prideful intellect.
It's the prideful intellect that raises itself against what is most properly placed at the highest place. Which is what God is, whatever that is, whatever it is, it's not the intellect.
It (intellect) is a subordinate spirit. "And if it isn't, then it becomes aimed essentially, at something approximating hell, and perfectly capable of creating it, and then perfectly capable of ruling in it."
The parable continues...
When God calls Lucifer on his rebellion, he says, If you but repent, you could be welcomed home. And Lucifer says: Well, I am the sort of spirit that even if I once repented, I would be instantly tempted to merely repeat my mind mistake.
And he says, as well, I would rather rule in hell than serve in heaven.
"Hey man, there's a choice for you at the crossroads. "