Episode 179 - By The Envy Of The Devil, Death Entered The World

The Fathers agree that the primary sin of Satan, the sin which caused him to rebel against God and fall from heaven, and the sin that he introduced into the heart of man through his cunning, was the sin of envy.

Lucifer was envious of what God had planned for man. He was envious that man had been made in God's image and when he was perfected, man would surpass the angels in glory. Instead of rejoicing in God's goodness, Lucifer was eaten up with murderous envy- He didn't just want what man was promised, he wanted to destroy man and keep him from ever attaining it.