Source: Optimism (1903)by Helen Adams Keller.

Complete Sentence: although the world is full of suffering, it is full also of the overcoming of it. My optimism, then, does not rest on the absence of evil, but on a glad belief in the preponderance of good and a willing effort always to coöperate with the good, that it may prevail. I try to increase the power God has given me to see the best in everything and every one, and make that Best a part of my life.