No true evil comes to being overnight, it is born out of one bad decision after another.

Watch your thoughts; they become words. Watch your words; they become actions. Watch your actions; they become habit. Watch your habits; they become character. Watch your character; it becomes your destiny.

– Mahatma Gandhi

And a day will come when you will wake up far from the innocence of youth;
when light no longer shines from your eyes;
and goodness no longer flows from your heart.

That day, when it comes my friend, you will be truly evil and salvation becomes a long forgotten dream. So watch your thoughts, that is where the fight against evil is fought.