"When I do good I feel good.  When I do bad I feel bad."- Abraham Lincoln

What this quote trying to say is when you help someone or do something good in just for no reason just to be nice in the end you will be feeling to in the inside. Like for example if you help an older person or if you just help your mom or even when you reached the goal that makes you feel good . And when you do those good things you end up feeling good in the inside you end up feeling happy.Also what the quote is saying is that if you do something bad you won't feel good at all you will feel guilty. For example, if you brake something or take something that is not your's you end up feeling guilty, sad that is what means you feel bad when you do something bad.