The Sin Of Pride

Question:

Why did Lucifer and 1/3 of God’s angels make the decision to not serve God?

Answer:

As for the particular sin the bad angels committed, many theologians believe that in their pre-fallen state the angels were given a foreknowledge of humans (who would be inferior to them), as well as a foreknowledge that God himself (the second Person of the Trinity) would be incarnated as a man and redeem the universe through his death on the cross.

This revelation angered Lucifer because it meant he and the other angels would have to worship God incarnate (the human form). Lucifer and the other angels who fell were so proud of being superior to men that their overweening arrogance wouldn’t allow them to worship Jesus Christ the God-Man. This refusal–this non serviam–stemmed from pride.