I have a question that I have often wondered about.
Where did evil originally come from?
We know that Satan who had every advantage, and became proud and puffed up, began to desire the worship that was rightly given to the Lord.
However we also know for every cause including evil, there has to be a causative agent. Since in the presence of God, evil cannot exist, how did Satan become evil?
Ezekiel 28:11-15 tells us that when created, Satan was the model of perfection and beauty. And then wickedness was found in him. Rev. 12:4 hints that when Satan rebelled 1/3 of the angels sided with him. These verses imply that like God, the angels have the knowledge of both good and evil and the agency to choose one over the other. Most have chosen good out of love for and obedience to their Creator. But some didn’t.
Adam and Eve were warned not to the eat the apple because it would give them the knowledge of good and evil (Genesis 2:17) and result in their deaths. We know that a mere apple doesn’t have this power, so something more sinister must have been going on.
I believe that in disobeying God they awakened in themselves the knowledge of their own agency. The problem is that unlike God and the angels, man lacks the power to resist evil and will always yield to its attraction. (Jeremiah 17:9) This of course resulted in their deaths just as God had warned them. They also had to be expelled from the garden because having succumbed to the power of evil they could not be allowed to eat the fruit of the tree of life and regain their immortality. As Satan has clearly demonstrated the notion of even one evil immortal being has brought devastating consequences upon the creation.
Adam and Eve had already yielded to the power of evil. The only things God could do without violating their freedom of choice was to limit their lifespans, thereby limiting their ability for evil works, and promise them a Redeemer who could restore their immortality if they chose to allow it.