“It may make a difference to all eternity whether we do right or wrong today.”

-      James Freeman Clarke

What James Freeman is trying to say is that, later on in life, your actions from the present can affect you. If you do the right thing now and then your future consequences will be positive. But, if you do the bad things now, then it can affect you negatively in the future. You decide your own future by the actions that you decide to do today.