It was discovered by an artist by the name of Judith Baca. She also painted bridge murals, wall murals, and many things in recreation centers....where often times there was gang grafitti on the walls. She even was able to get rival gangs to work together for a short time, to paint some of these murals, in poverty stricken areas. The phrase "I'd rather spend one day as a lion than a hundred as a lamb" was one of those phrases she discovered in a mural on a wall. This is the link about her as the artist and the murals. It is pretty interesting. You can find some more about how she discovered that in the paragraph entitled "Teachers and other jobs". http://en.wikipedia.org/wiki/Judy_Baca
The quote, " I'd rather live a day as a lion, than a lifetime as a lamb" came from a wall that was photographed in early 70's. This quote was discovered by Judy Baca during her career as an artist. It means it is better to live life with courage than shyness or low self esteem.