Musar על בבא קמא 235:11

I believe that in the many instances when the Talmud justifies certain rulings by the statement אדם חשוב שאני, that we apply different yardsticks to morally high-ranking people, the Talmud wants to emphasize that the law is different when applied to such people. It is not merely a voluntary abrogation of one's rights. When the Talmud speaks of "doing one's duty in the eyes of Heaven," however, it is something else again. Such considerations apply where for one reason or another the human tribunal is unable to enforce a certain ruling.