Life engenders life. Energy creates energy. It is by spending oneself that one becomes rich. (Sarah Bernhardt, 19th-20th century French stage actress)
This may sound like either a science lesson about life and energy or a philosophical statement about life itself. The science lessons are important, but Bernhardt no doubt is simply trying to help us understand something even more important. When we spend ourselves for the good of others, we both benefit and become that much richer in character and value.
The generous will prosper; those who refresh others will themselves be refreshed (Proverbs 11:25).