It is the evil that kills the wicked (Psalms 34:22).
Chassidic philosophy teaches that God gives vitality, a life-sustaining force, only to the good and positive in the world. Evil can exist only because it derives its "nutrition" from that which is good and positive, just as a parasite derives its nutrition from the host. Evil could not continue to exist unless it somehow attached itself to the good, but while it is the nature of good to give of itself, the parasitic evil only takes and thus drains the good of its strength.
Parasites ultimately destroy themselves. Because a parasite can only exist by feeding on its host, and since it thereby weakens the host, it is essentially working toward its own destruction. If it never lets go, it will kill the host, its source of sustenance, and it too will die.
Fear of punishment need not be our only deterrent from doing wrong. Just as the parasite that sucks the lifeblood from its host can temporarily thrive, so may wrongdoing appear to be profitable for a short term. Ultimately, however, evil destroys itself.
Looking only at the short-term consequences and ignoring the inevitable is a common mistake. The Talmud states that truly wise people look to the future and give serious thought to the ultimate consequences of their behavior, rather than focusing upon the momentary gratification.