From A Path With Heart, by Jack Kornfield, page 36:
"Martin Luther King, Jr., understood this spirit and brought it alive in the darkest period of the civil rights marches. His church had been bombed and a number of people killed. He called upon the power of the heart to face this suffering and through this come to freedom. He said:
' We will match your capacity to inflict suffering with our capacity to endure suffering. We will meet your physical force with Soul Force. We will not hate you, but we cannot in all good conscience obey your unjust laws. But we will soon wear you down with our capacity to suffer. And in winning our freedom we will so appeal to your heart and conscience that we will win yours in the process.'"