हितोपदेशं शृणुयात् कुर्वीत च यथोदितम् ।
विदुरोक्तमकृत्वाभूत्कौरवः शोकशल्यभाक् ॥
hitopadesham shRuNuyAt kurvIta cha yathA uditam ।
viduroktam akRutvA bhUt kauravaH shoka shalya bhAk ॥
You must listen to people when they are advising for your own well being - and do as they say. Kaurava listened to Vidura, but did not do as he said. As a result he met with lot of grief.