If bad things happen to others and you don't speak up, chances are bad things will happen again and when it's your turn no one will speak up because you've been silent for so long. Many people have a "none of my business" mentality when it comes to hurting others.
Evils persist in your neighborhood and in the world at large because many good people have chosen to do nothing, perhaps because it does not directly affect them or the people they serve. But the truth is, the evil people refuse to speak out against will one day befall them.
I Remember this quote by a famous man that goes like this: They come for the Jews, but I don't speak out against them just because I'm not Jewish. They also came for Greek and I refused to complain because I am not Greek. Now that they have come to me, no one can stand against them.
Acting against evil does not mean acting beyond one's ability. This means doing your part to solve difficult problems. When good people stand against bad people, bad people are greatly reduced. On your street corner there is a criminal with whom you can fight. If everyone takes care of the evil in their vicinity, there will be no more evil left.
When you act so naturally that you don't care about others when they hurt, if this turns out to be your own situation, people will turn their backs on you too. In the dark of the night, there is no use having a lantern without lighting it. Likewise, having a good heart in a world full of darkness and evil without using it for good is useless.
It is the kindness you show in the face of evil that will make all the difference in the world. You don't have to be a superhero or have superpowers to make a positive impact on the world. From your street corner, let the light within you illuminate those around you. Note that the persistence of bad deeds only proves the silence of the good people.
Thank you.