Once upon a time in an epoch before this creation Lucifer was found to have sinned against God almighty. Not only that, but Lucifer led a portion of the angels into his rebellion and there was war in heaven. Michael stood with Gabriel and defeated Lucifer and cast him and His followers out of the sides of the north far from the presence of God.
God, about to cast Lucifer into the lake of fire, heard him speak this challenge:
“You are unrighteous for even those you are about to create cannot serve you without sinning just as I have. Before you condemn me to an eternal punishment prove that man can succeed where I have failed. If you prove they can walk perfectly before you then I will accept my punishment but if they fail I will in nowise suffer torment. Put now therefore two trees in the midst of your garden and give them free will to choose. As they choose so will be both our fates.”
“So be it, lo I have put two trees in the midst of my paradise: the tree of life and the tree of the knowledge of good and evil. As man so chooses thus shall be both your fates.”