'ripples of hope'

Robert F. Kennedy, from the Day of Affirmation speech delivered at the University of Cape Town, 1966:
Each time a man stands up for an ideal, or acts to improve the lot of others, or strikes out against injustice, he sends forth a tiny ripple of hope, and crossing each other from a million different centers of energy and daring, those ripples build a current which can sweep down the mightiest walls of oppression and resistance.
I wasn't familiar with this, and listening to it gave me heart after a week and a half of feeling hopelessly small.

Discovered thanks to President Obama.