After the wrong choice and action of the first human beings the elohim had no other choice than to bring over man the curse He had warned them for. But out of love for His creatures He also provided straight away a solution against the curse of death and gave man a second chance.
About the origin or source of evil there are many discussions. In this article I look at the time where badness entered in the world of man and where we have to look for the source of evil or badness.
Nature and everything in it was in a perfect natural peaceful balance. By the wrong choice made by the first human beings there came a crack in perfection and in the relationship between the Creator and other creatures.
Man knew that The Word of God brought life and order and got their mind wondering if they could not become as wise and mighty as God. The inner voice of man or the nachash is of self-esteem and brings deception when allowing oneself to be carried away by the temptation, falling into trickery, treachery,and insincerity.
God made Himself a beautiful Royal Garden, the Gan Eden with in the midst of it a Etz HaDa'as Tov v'Rah or Tree of moral of which God asked man not to touch it nor eat from the fruit that gives knowledge about good and evil because they would then certainly die. But we come to see that the nachash (temptation) was to strong for the isha and she got her husband involved in her act of disobedience to the Elohim.