Combatting Inner Evil
The Kotzker Rabbi said: "The battle in a man's heart against evil impulses may be likened to warfare. Strategy must be employed in the inner battle exactly as in war. When the general succeeds in entrenching his position against the foe at one place, he does not rest content with his achievement lest the enemy assail him elsewhere. Likewise, if a man immunzes against a particular fault, he must guard himself against succumbing to another."
Source: Siach Sarfei Kodesh