Our battle with evil should not be built upon the likelihood of vanquishing it in this life but must been recognized as a virtuous action no matter its outcome; that is a vital step in our ability to cope with the emotional fallout when evil comes. As Alfred says when quoting Wayne's idealistic father, we fall "so that we might learn to pick ourselves up." But implicit in that advice is the understanding that the act of rising from a fall is an essential part of overcoming that failure—a claim further bolstered by Wayne's realization in Batman Begins that "it's not what I am underneath, but what I do that defines me."
Fear, failure, suffering, and sin are inescapable components of our fallen human condition, and while we can resist them in this life, they will never be eliminated from "this vale of tears." Heroism and the confrontation of evil—a confrontation most often achieved through suffering—is the only way to truly grapple with the problem. To paraphrase Alfred, we must learn to get back up; to rise again, and press ever forward towards the light.
In The Dark Knight, Harvey Dent reminds Batman that "the night is darkest just before the dawn." Despite the darkness of Aurora, we must hold fast to the belief that evil men and their actions—much as they may consume us—are mere blips on the road to salvation.
For us, the journey is the destination, and that journey through the darkness of this life is never undertaken alone, for we are ever accompanied by The Dawn Himself: "Yea, though I walk through the valley of the shadow of death, I will fear no evil: for thou art with me; thy rod and thy staff, they comfort me" (Psalm 23:4).