O sire, I would impart to thee another sacred lesson productive of great fruits, and which is the highest of all teachings, viz., virtue should never be forsaken from desire, fear, or temptation, nay, nor for the sake of life itself. Virtue is everlasting; pleasure and pain are transitory; life is, indeed, everlasting but its particular phases are transitory.

In plain words: Vidura tells King Dhritarashtra his most important lesson: never give up doing what is right, whether out of desire, fear, greed, or even to save your own life. Goodness lasts forever, but pleasure and pain come and go. The life within us goes on, but each stage of it passes.