"It is in dying that we give life to others.", a quote from a wise man and I believe it's true though sometimes not easy. 
Only a life lived for others is a life worthwhile. ~Albert Einstein

Happiness cannot come from without. It must come from within. It is not what we see and touch or that which others do for us which makes us happy; it is that which we think and feel and do, first for the other fellow and then for ourselves. ~Helen Keller 

The best way to find yourself is to lose yourself in the service of others. ~Mahatma Gandhi

For it is in giving that we receive;
it is in pardoning that we are pardoned;
and it is in dying that we are born to eternal life.~St. Francis of Assisi