“I alone cannot change the world, but I can cast a stone across the waters to create many ripples.”
- Mother Teresa, as seen in this collection on goodreads.

A few more quotes, from the same source:

“If you are humble nothing will touch you, neither praise nor disgrace, because you know what you are.”
― Mother Teresa

“I can do things you cannot, you can do things I cannot; together we can do great things.”
― Mother Teresa

“We know only too well that what we are doing is nothing more than a drop in the ocean. But if the drop were not there, the ocean would be missing something.”
― Mother Teresa

Mother Teresa was recently canonized within the Catholic Church: Saint Teresa of Calcutta (Kolkata).