Lucifer' means 'light-bringer' and this should begin to clue us in to his symbolic importance. The story is that God threw Lucifer out of Heaven because Lucifer had started to question God and was spreading dissension among the angels. The truth may just as easily be that Lucifer resigned from heaven. Probably what really happened was that Lucifer came to hate God's kingdom, his sadism, his demand for slavish conformity and obedience, his psychotic rage at any display of independent thinking and behavior. Lucifer realized that he could never fully think for himself and could certainly not act on his independent thinking so long as he was under God's control.
Lucifer is the embodiment of reason, of intelligence, of critical thought.
He stands against the dogma of God and all other dogmas. He stands for the exploration of new ideas and new perspectives in the pursuit of truth. God demands that we believe everything that he tells us, and that we do everything that he says without questioning. Why of course. Wait a minute, this doesn't seem very nice.