Why does evil exist?
This question and others (such as “Why do we suffer?”) have plagued humankind since time immemorial.
There are Kabbalistic discussions about the existence of evil, but the most powerful and life-changing answer is that evil exists in order to offer contrast with good.
The existence of evil enables us to
Did you ever notice that the further people are from truth, the more they consider someone who turns away from evil to be a fool?
When there is no truth in the world, anyone who wants to turn away from evil has no choice but to play the fool.
—Rebbe Nachman of Breslov, The Aleph-Bet Book
Photo: Nachal Nakarot at night, freeisraelimages.com