"If your so-called friends urge you to do anything you know to be wrong, you be the one to make a stand for right, even if you stand alone. Have the moral courage to be a light for others to follow." 

Thomas S. Monson

I think this is just another way to say be a leader not a follower. You have to give others hope not take it away. You have to set an example for your peers, but it has to be a positive example. Do something like offer food to homeless people or help an elderly woman with groceries or help an elderly man walk across the street. If you see a mugging or someone doing something bad, you have to turn into an authoritative figure and stop the negativity. You can't turn to corruption. You must abstain from negativity and corruption.