To fight evil face-to-face is futile. But we can cut off its supply.
Between good and evil lies a neutral ground, a battlefield—the realm of all things permissible. All supplies to the enemy must pass through this realm. Because evil has no power of its own—it lives entirely off the scraps thrown to it from above.
By taking all that is permissible and using it only for good, honestly and uprightly, with purpose that transcends our own selves, the supply lines are broken.
When every activity of life becomes a way to know G‑d, evil simply withers away and dies.
Tanya, chapter 37.