That's an old countercultural slogan from the 1960s in America. It means:
Never give up. Believe in the good.
Here is a little phrase I have on my refrigerator door. (Americans often put photos or magnets with phrases on their metal refrigerator doors, because they see them every day that way -- like a household bulletin board.)
WHAT IS COURAGE?
C = confronting the dragons
O = overcoming the obstacles
U = understanding the risks
R = really living (I love that one especially.)
A = always believing
G = going the distance (to persist with dedication and intention)
E = experiencing the best
To live requires courage. And to live well - for ourselves and others - requires courage and love.