As long as one does not believe that he is good, he cannot believe that another is good. Only a person that believes that his own essence is good, and accustoms himself to give and not take (thereby removing the veil of the "I") will be able to expand the light outward toward another. A person who has worked on himself to see himself as good, but still has a habit of taking and not giving, will find a barrier created by his desire to take. Such a person might think of himself as good, with a bad garment, but of another individual as inherently bad. Why? Because he has set up a barrier between himself and another. His desire to take makes him a distinct entity, so although he knows that he is good with an evil garment, he will not be able to apply that attitude toward others. The desire to take is a barrier, and he wants to keep the goodness for himself. His eye will be like that of Bilaam, "an evil eye". Only if he has also developed a desire to give can he expand the good found in him to another, and by doing so, he will see the entire creation as good. This expansion of goodness to the whole world will bring out in him the world of inner, true love that unifies all of the creations.
(Rabbi Itamar Schwartz)