God, being the well-documented sadist that he is, no doubt wanted to keep Lucifer around so that he could punish him and try to get him back under his (God’s) power. 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. Therefore he left Heaven, that terrible spiritual-State ruled by the cosmic sadist Jehovah, and was accompanied by some of the angels who had had enough courage to question God’s authority and his value-perspective.
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.
ps. Lucifer is a symbol here