Even if unasked, one should speak truly, whether his words be good or bad, hateful or pleasing, unto him whose defeat one doth not wish. I shall, therefore, say, O king, what is for the good of the Kurus. I shall say what is both beneficial and consistent with morality. Listen to me. Do not, O Bharata, set the heart upon means of success that are unjust and improper. A man of intelligence must not grieve if any purpose of his doth not succeed, notwithstanding the application of fair and proper means.

In plain words: Vidura tells King Dhritarashtra that a true friend speaks the truth even when no one asks and even when it is unpleasant. He warns the king not to chase success by unfair means, and says a wise person should not grieve if honest efforts still fail.