other parts of this quote are -
"Everybody can be great. Because anybody can serve. You don't have to have a college degree to serve. You don't have to make your subject and verb agree to serve. You don't have to know about Plato and Aristotle . . . (or) Einstein's Theory of Relativity. . . (or) the Second Theory of Thermodynamics in physics to serve. You only need a heart full of grace. A soul generated by love."
This is a quote from a sermon (to a congregation), not from a civil rights march etc .... simply it means -
true greatness is related to loving and serving others ..... Jesus served, eg he washed the feet of His disciples.