Isaiah 14:12-14 shows that 'self-exaltation' and 'pride' were the cause of Satan's rebellion.

.............He was perfect when he was created and gifted with great wisdom and beauty.
....................Ezekiel 28:17 says
............"Thine heart was lifted up because of thy beauty."

........................Lucifer possessed rare gifts. So because of these gifts and abilities, God gave him a high position of His creation.