"It may make a difference to all eternity whether we do right or wrong today." James Freeman Clarke 

To me this means that if we want to make a difference today is the day to start. In other words if you always postpone things for tomorrow, tomorrow may not come. If we want to change the world and how people view it we have to learn to do something about it today. Don't wait for a better tomorrow be that better tomorrow. I want to make a difference in this world and I now understand what James is saying. He's saying to act now but to do it in a ethical manner. It has to be this way because if we try to change the world or make a difference the wrong way then that will follow us. Things will be revealed and later on the thing you did won't even matter as much as what you did wrong. An example of this is Martin Luther King he didn't like how things were so he decided to do something about it. People remember him for it because he did it the right way. In conclusion we must learn to choose the right because that will lead us to the right path. Once we are in that path then we will learn to make a difference,