"Goodness is the only investment that never fails."-Henry David Thoreau

The statement explains that giving your time to do something good just because it's good never backfires. You don’t expect anything back so you never feel bad. Instead you feel great because you did a good thing and helped someone or did something good. For example helping a friend who's in need even when they don't ask you too. You don't expect anything back but they will always be grateful. They may even help you out when you are in need. It's just like karma.