Pay it forward~~
Paying it forward is a third-party beneficiary concept that involves doing something good for someone in response to a good deed done on your behalf or a gift you received. When you pay it forward, however, you don't repay the person who did something nice for you. Instead, you do something nice for someone else. For example, if someone changes your tire while you are stranded on the highway, you might shovel your elderly neighbor's walkway after a snow has fallen.