The prophet Ezekiel tells us that Lucifer was “the model of perfection, full of wisdom and perfect in beauty.” (Ezekiel 28:12) Prior to the creation of Adam, we are told “…the morning stars sang together, and all the sons of God shouted for joy.” (Job 38:7) We can only speculate on the length of time that Lucifer enjoyed the fellowship of his heavenly Father, Michael the archangel, and the myriads of angelic beings that dwelt in heaven. Additionally, Ezekiel tells us that, after the creation of Adam, Lucifer was “anointed as a guardian cherub” of the Garden of Eden.
However, Lucifer soon became discontent with his position. Pride and personal ambition took root in his heart and mind as he contemplated ruling his own kingdom. (Ezekiel 28:14-17) His goal was to transfer man’s allegiance from God to himself. Sadly enough, his love and devotion to God waned, and his overinflated ego consumed him. “How you have fallen from heaven, O star of the morning, son of the dawn! … You said in your heart I will ascend to heaven; I will raise my throne above the stars of God…I will ascend above the heights of the clouds; I will make myself like the Most High.” (Isaiah 14:12-14)
Lucifer was the first being ever to sin. Therefore, he could not have learned it by observing others. His sin was generated from his own heart when he allowed pride to enter. After Adam’s disobedience, the death penalty was pronounced and executed upon our race. No doubt Satan’s plans were frustrated. It was not his original intention to rule a race destined for death.
Regarding where Lucifer was when his thoughts turned to sin, the Scriptures are unclear. As the guardian of Eden, his sin may have occurred while on earth, as he observed Adam and Eve. Or it could have occurred while he was in heaven. The important point is that God dealt with Lucifer’s sin. He fell out of God’s favor and was confined to earth’s atmosphere in “chains of darkness until the judgment of the great day.” (Jude 6)