There is this wonderful interview that was done with Mother Teresa in TIME Magazine in 1989 by Edward D. Desmond, in which he asked her if she thought that she had any special qualities. Her answer: "I don't think so. I don't claim anything of the work. It's His work. I'm like a little pencil in His hand. That's all. He does the thinking. He does the writing. The pencil has nothing to do it. The pencil has only to be allowed to be used. In human terms, the success of our work should not have happened, no? That is a sign that it's His work, and that He is using others as instruments - all our Sisters. None of us could produce this. Yet see what He has done."
When we give consent to where He puts us and do what He asks us to do with a big smile great miracles can happen.