The Bible makes it clear that Satan is real, and that he is ultimately behind all the evil that goes on in the world. Before he rebelled against God (long before the human race was created), the world was perfect; sin and evil didn’t exist. But now we live in a fallen, twisted, sin-infested world – and Satan is the reason.
But on the other hand, Satan is not all-powerful, nor does he directly cause every bad thing that happens to us.
By His death and resurrection, Jesus triumphed over all the forces of evil – those in our heart and those in the world.
Each one is tempted when, by his own evil desire, he is dragged away and enticed. Then, after desire has conceived, it gives birth to sin.
Billy Graham – Wisdom For Each Day