Sulabhah purusha rajan satatam priyavadinah, apriyasya tu pathyasya vakta shrota cha durlabhah. “Oh, King! It is easy to find people who always talk in (your) favor. But people who speak or listen to ‘words not in (your) favor, yet in your welfare’ are rare to find!”
The verse appears in the Udyoga Parva of the Mahabharata, and also in the Ramayana.