The Tanya explains that Hashem reluctantly created evil in the world. The analogy was to someone who is asked to deliver a gift to someone who he strongly dislikes. He fulfills his task without even looking at the person. The same is true of how evil became a reality. Hashem certainly would have preferred not to have evil exist. However, the Tanya explains, evil became the device necessary in order to reward the righteous for separating themselves from it. And similarly, it was going to be the cause for punishing the wicked for attaching themselves to it. We are meant to constantly be aware of the good and evil in the world. This is the role of the Jew. We achieve קדושה by separating ourselves from the profane and from the other nations. We also separate from the clean and unclean animals. When we attain this קדושה, we are elevated because we have succeeded in not allowing evil to enter our lives.