I strongly believe that mercy is the great duty.
Explanation: This line has been taken from the poem 'यक्षयुधिष्ठिरसंवादः'. This is the concluding verse from the dialogue between Yudhisthira and Yaksha.
While living in the forest, once the Pandavas feels thirsty. At that time Yudhisthira sends Sahdev to fetch water from the nearby pond. But after a long time, he did not return, So Yudhisthira sent Nakul, Bhima and Arjuna one by one to fetch the water. But they too didnt return. So ultimately, Yudhisthira himself goes for water. He finds all his brothers lying unconscious there. When he tries to drink water from the pond, an invisible Yaksha stops him and aks him to answer his questions. Yudhisthira answers all his questions intelligently. Yaksha was pleased with his answers. So he brought all his brothers back to life. In the answer to the last question, Yudhisthira mentiones that mercy is the greatest duty. The answers given by Yudhisthira reflects his politeness, confidence and love for his brothers.