Think it was C S Lewis that once wrote something about that in order to be so bad, to have sunk so low requires a great fall, so Satan must have been very good at one time. Tradition has him leading the chorus of angels in praise of God, and desiring that praise for himself. It is apparent from scripture and tradition that not all angels are created equally, they have different powers and different roles. An arch-angel is suppose to be most powerful and tradition has Satan fighting with those, so he must be very powerful to pick that fight.
I have a question on Lucifer (now, Satan). Why was Lucifer given the highest role and why is he regarded as one of the most beautiful angels God made? Aren't all the angels equally beautiful in God's sight?
