In the Mahabharata there are many versions of the exposition of Dharma pegged on to the events and circumstances. The entire tale records nuances of the complex human nature comprising shades of good and bad.
Lord Krishna talked of the individual's Dharma with respect to one's duty and salvation. This teaching took place in the war front. Bhishma spoke of the values of life while awaiting death lying on the bed of arrows.
Who expounds the Dharma and who listens to it becomes significant and enhances the value of the Dharma taught, pointed out Dr. Sudha Seshaiyan in a lecture. All these clarifications emphasise that the coexistence of good and evil poses a constant challenge to the individual and that the values of Sanatana Dharma have to be upheld against this backdrop.
Dhritarashtra typifies the individual who is aware of right and wrong but allows unrighteousness to usurp his conscience. This becomes explicit in his message to the Pandavas through Sanjaya after their successful completion of the period of exile. When Yudhishtira made known his demand for Indraprastha, the rightful possession of the Pandavas, Dhritarashtra turned the tables against him. He was not willing to give it back to them. Instead he merely tells Yudhishtira to woo peace at all costs and not invite a war, that is, forget Indraprastha.
This message is symbolic of his blindness — not merely the physical handicap, but the inner rot that manifests in his refusal to live and act according to Dharma. He never opens his inner eye. He is well aware of his son's faults. He is unable to get out of his blind affection towards his son. He is sly and cunning as well.
Equally, the king is aware of the virtues of the Pandavas. Though treated badly they had never given up their commitment to righteousness. Neither had they ever been untruthful. They had always been dutiful to him. But Yudhishtira tells Sanjaya that only if Indraprastha is given to them they will not have war. This is the least that he can ask after all the indignities and sufferings he and his family members underwent so far.