When we look upon the person who is the cause of his pleasure with the eyes with which we imagine he must look upon him, his benefactor seems to stand before us in the most engaging and amiable light.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“When we see one man assisted, protected, relieved, by another, our sympathy with the joy of the person who receives the benefit serves only to animate our fellow-feeling with his gratitude towards him who bestows it. When we look upon the person who is the cause of his pleasure with the eyes with which we imagine he must look upon him, his benefactor seems to stand before us in the most engaging and amiable light. We readily therefore sympathize with the grateful affection which he conceives for a person to whom he has been so much obliged; and consequently applaud the returns which he is disposed to make for the good offices conferred upon him.” source