"All that it takes for evil to triumph is for good people to do nothing." - Sir Edmund Burke, 1769.
In my opinion I think this quote is saying to us that if we just stand by and do nothing, bad things will keep happening and will make the world worse and that things will not get fixed. An example of this is everyday bullying. It is an issue because many people are bullied and the bystanders don't do anything to stop the bully.